Avoid stamping builds when not actually building

Author: shs96c

rake-tasks/buck.rb

@@ -59,7 +59,9 @@ def self.buck_cmd(command, args, &block)
 
  args ||= []
  buck.push(command)
- buck.push('--stamp-build=detect')
+ if command == 'build' || command == 'test' || command == 'publish'
+ buck.push('--stamp-build=detect')
+ end
  buck.push(*args)
  puts buck.join(' ')