appveyor: remove appveyor configuration

This configuration to run the checks on appveyor looks very old and
unused since it still refers to glide for dependency management. We
remove the file as it no longer serves a purpose.

appveyor.yml

@@ -1,22 +0,0 @@
-version: "{build}"
-
-clone_folder: c:\projects\src\github.com\btcsuite\btcwallet
-
-environment:
- PATH: c:\projects\bin;%PATH%
- GOPATH: c:\projects
- GORACE: halt_on_error=1
-
-init:
- - go version
- - go get -u github.com/Masterminds/glide
- - go get -u github.com/davecgh/go-spew/spew
-
-install:
- - glide install
-
-build_script:
- - ps: go get $(glide novendor)
-
-test_script:
- - ps: go test -race $(glide novendor)