Merge pull request #182 from haberman/bazelfix

Fixed upb_proto_library() logic for calculating output dir.

bazel/upb_proto_library.bzl

@@ -37,10 +37,8 @@ def _get_real_roots(files):
     return roots.keys()
 
 def _generate_output_file(ctx, src, extension):
-    if _is_bazel:
+    real_short_path = _get_real_short_path(src)
-        real_short_path = _get_real_short_path(src)
+    real_short_path = paths.relativize(src.short_path, ctx.label.package)
-    else:
-        real_short_path = paths.relativize(src.short_path, ctx.label.package)
     output_filename = paths.replace_extension(real_short_path, extension)
     ret = ctx.actions.declare_file(output_filename)
     return ret