Fix _ImportParser() error if property is imported from oem partition. am: 96c88287 am: 3065c1b1

    """Parses the build prop in a given import statement."""

    tokens = line.split()

    if len(tokens) != 2 or tokens[0] != 'import':

    if tokens[0] != 'import' or (len(tokens) != 2 and len(tokens) != 3) :

      raise ValueError('Unrecognized import statement {}'.format(line))

    if len(tokens) == 3:

      logger.info("Import %s from %s, skip", tokens[2], tokens[1])

      return {}

    import_path = tokens[1]

    if not re.match(r'^/{}/.*\.prop$'.format(self.partition), import_path):

      raise ValueError('Unrecognized import path {}'.format(line))