Fix deadlocks in setaccount, sendfrom RPC calls

SendMoney*() now requires caller to acquire cs_main.
GetAccountAddress() now requires caller to acquire cs_main, cs_mapWallet.

Ordering is intended to match these two callchains[1]:

1. CRITICAL_BLOCK(cs_main)
    ProcessMessage(pfrom, strCommand, vMsg)
        AddToWalletIfMine()
              AddToWallet(wtx)
                  CRITICAL_BLOCK(cs_mapWallet)

2. CRITICAL_BLOCK(cs_main)
    ProcessMessage(pfrom, strCommand, vMsg)
        AddToWalletIfMine()
              AddToWallet(wtx)
                  CRITICAL_BLOCK(cs_mapWallet)
                      walletdb.WriteName(PubKeyToAddress(vchDefaultKey), "")
                          CRITICAL_BLOCK(cs_mapAddressBook)

Spotted by ArtForz.  Additional deadlock fixes by Gavin.

[1] http://www.bitcoin.org/smf/index.php?topic=4904.msg71897#msg71897

db.cpp

@@ -668,8 +668,8 @@ bool CWalletDB::LoadWallet()
 #endif
 
     //// todo: shouldn't we catch exceptions and try to recover and continue?
-    CRITICAL_BLOCK(cs_mapKeys)
     CRITICAL_BLOCK(cs_mapWallet)
+    CRITICAL_BLOCK(cs_mapKeys)
     {
         // Get cursor
         Dbc* pcursor = GetCursor();

main.cpp

@@ -4046,10 +4046,9 @@ bool CommitTransaction(CWalletTx& wtxNew, CReserveKey& reservekey)
 
 
 
+// requires cs_main lock
 string SendMoney(CScript scriptPubKey, int64 nValue, CWalletTx& wtxNew, bool fAskFee)
 {
-    CRITICAL_BLOCK(cs_main)
-    {
     CReserveKey reservekey;
     int64 nFeeRequired;
     if (!CreateTransaction(scriptPubKey, nValue, wtxNew, reservekey, nFeeRequired))
@@ -4068,13 +4067,14 @@ string SendMoney(CScript scriptPubKey, int64 nValue, CWalletTx& wtxNew, bool fAs
 
     if (!CommitTransaction(wtxNew, reservekey))
         return _("Error: The transaction was rejected.  This might happen if some of the coins in your wallet were already spent, such as if you used a copy of wallet.dat and coins were spent in the copy but not marked as spent here.");
-    }
+
     MainFrameRepaint();
     return "";
 }
 
 
 
+// requires cs_main lock
 string SendMoneyToBitcoinAddress(string strAddress, int64 nValue, CWalletTx& wtxNew, bool fAskFee)
 {
     // Check amount

rpc.cpp

@@ -315,12 +315,11 @@ Value getnewaddress(const Array& params, bool fHelp)
 }
 
 
+// requires cs_main, cs_mapWallet locks
 string GetAccountAddress(string strAccount, bool bForceNew=false)
 {
     string strAddress;
 
-    CRITICAL_BLOCK(cs_mapWallet)
-    {
     CWalletDB walletdb;
     walletdb.TxnBegin();
 
@@ -354,7 +353,7 @@ string GetAccountAddress(string strAccount, bool bForceNew=false)
 
     walletdb.TxnCommit();
     strAddress = PubKeyToAddress(account.vchPubKey);
-    }
+
     return strAddress;
 }
 
@@ -368,7 +367,15 @@ Value getaccountaddress(const Array& params, bool fHelp)
     // Parse the account first so we don't generate a key if there's an error
     string strAccount = AccountFromValue(params[0]);
 
-    return GetAccountAddress(strAccount);
+    Value ret;
+
+    CRITICAL_BLOCK(cs_main)
+    CRITICAL_BLOCK(cs_mapWallet)
+    {
+        ret = GetAccountAddress(strAccount);
+    }
+
+    return ret;
 }
 
 
@@ -392,6 +399,8 @@ Value setaccount(const Array& params, bool fHelp)
         strAccount = AccountFromValue(params[1]);
 
     // Detect when changing the account of an address that is the 'unused current key' of another account:
+    CRITICAL_BLOCK(cs_main)
+    CRITICAL_BLOCK(cs_mapWallet)
     CRITICAL_BLOCK(cs_mapAddressBook)
     {
         if (mapAddressBook.count(strAddress))
@@ -475,9 +484,13 @@ Value sendtoaddress(const Array& params, bool fHelp)
     if (params.size() > 3 && params[3].type() != null_type && !params[3].get_str().empty())
         wtx.mapValue["to"]      = params[3].get_str();
 
+    CRITICAL_BLOCK(cs_main)
+    {
         string strError = SendMoneyToBitcoinAddress(strAddress, nAmount, wtx);
         if (strError != "")
             throw JSONRPCError(-4, strError);
+    }
+
     return wtx.GetHash().GetHex();
 }
 
@@ -752,6 +765,7 @@ Value sendfrom(const Array& params, bool fHelp)
     if (params.size() > 5 && params[5].type() != null_type && !params[5].get_str().empty())
         wtx.mapValue["to"]      = params[5].get_str();
 
+    CRITICAL_BLOCK(cs_main)
     CRITICAL_BLOCK(cs_mapWallet)
     {
         // Check funds

ui.cpp

@@ -1933,6 +1933,8 @@ void CSendDialog::OnButtonSend(wxCommandEvent& event)
         bool fBitcoinAddress = AddressToHash160(strAddress, hash160);
 
         if (fBitcoinAddress)
+        {
+	    CRITICAL_BLOCK(cs_main)
 	    {
                 // Send to bitcoin address
                 CScript scriptPubKey;
@@ -1949,6 +1951,7 @@ void CSendDialog::OnButtonSend(wxCommandEvent& event)
                     EndModal(false);
                 }
 	    }
+        }
         else
         {
             // Parse IP address