Fix pip installs on Windows.

Author: arsharma1

setup.py

@@ -66,6 +66,7 @@ def initialize_options(self):
         print('Warning: mfg-inspector output is not fully implemented for '
               'Windows. OpenHTF will be installed without it.')
         self.skip_proto = True
+        return
 
     maybe_protoc = os.path.join(prefix, 'bin', 'protoc')
     if os.path.isfile(maybe_protoc) and os.access(maybe_protoc, os.X_OK):