Remove uneeded variables

Author: Geobert Quach

appveyor.yml

@@ -7,19 +7,17 @@ environment:
   global:
     CRATE_NAME: cobalt
     APPVEYOR_CACHE_SKIP_RESTORE: true
-    MSBUILD_NODE_CONNECTION_TIMEOUT: 0
 
   matrix:
     # Stable channel
     - TARGET: x86_64-pc-windows-msvc
       CHANNEL: stable
       TOOLCHAIN: msvc
-      PLATFORM: x86_64
+      
     # Beta channel
     - TARGET: x86_64-pc-windows-msvc
       CHANNEL: beta
       TOOLCHAIN: msvc
-      PLATFORM: x86_64
 
 install:
   - if "%TOOLCHAIN%" == "msvc" call "C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Auxiliary\Build\vcvars64.bat"