message: formatting: check for proto type errors
  tools/check_format.py was modified in to automatically fix
  protobuf type namespace errors in 'fix' mode, but it did not complain
  about them when run in 'check' mode. This commit fixes the lack of
  complaints from 'check' mode.
diff: @@ -126,6 +126,10 @@ def checkFileContents(file_path):
  printLineError(file_path, line_number, "over-enthusiastic spaces")
  if hasInvalidAngleBracketDirectory(line):
  printLineError(file_path, line_number, "envoy includes should not have angle brackets")
  + for invalid_construct, valid_construct in PROTOBUF_TYPE_ERRORS.items():
  + if invalid_construct in line:
  + printLineError(file_path, line_number, "incorrect protobuf type reference %s; "
  + "should be %s" % (invalid_construct, valid_construct))
  def fixFileContents(file_path):
  for line in fileinput.input(file_path, inplace=True):
  @@ -137,8 +141,8 @@ def fixFileContents(file_path):
  line = line.replace('<', '"').replace(">", '"')
  # Fix incorrect protobuf namespace references.
  - for error, replacement in PROTOBUF_TYPE_ERRORS.items():
  - line = line.replace(error, replacement)
  + for invalid_construct, valid_construct in PROTOBUF_TYPE_ERRORS.items():
  + line = line.replace(invalid_construct, valid_construct)
  sys.stdout.write(str(line))
  