Trigger only one build on appveyor

Author: harendra-kumar

appveyor.yml

@@ -3,9 +3,9 @@
 # variables here.  See https://github.com/composewell/packcheck for all
 # options and their explanation.
 
-#branches:
-#  only:
-#    - master
+branches:
+  only:
+    - master
 
 environment:
     # ------------------------------------------------------------------------