fixed the error when trying to perform get on channels

now it states that get cannot be used on channels

closes #623
closes #1085

CHANGELOG.md

@@ -11,6 +11,9 @@ at anytime.
 ### Security
   *
   *
+### Fixed
+  * fixed `get` on channel now it returns error that informs of `get` not supporting channels
+  * the message that is displayed can be more descriptive, and it is open for discussion
 
 ### Fixed
   * Fixed improper parsing of arguments to CLI settings_set (https://github.com/lbryio/lbry/issues/930)

lbrynet/daemon/Daemon.py

@@ -1630,8 +1630,11 @@ class Daemon(AuthJSONRPCServer):
 
         if not resolved or 'value' not in resolved:
             if 'claim' not in resolved:
-                raise Exception(
-                    "Failed to resolve stream at lbry://{}".format(uri.replace("lbry://", "")))
+                if 'certificate' in resolved:
+                    raise  Exception("Cannot use get on channels")
+                else:
+                    raise Exception(
+                        "Failed to resolve stream at lbry://{}".format(uri.replace("lbry://", "")))
             else:
                 resolved = resolved['claim']
         txid, nout, name = resolved['txid'], resolved['nout'], resolved['name']