Fix sphinx error in swift.common.utils

- Error was swift/common/utils.py:docstring of
  swift.common.utils.parse_content_type:7: ERROR: Unexpected
  indentation.
- Closes-Bug: #1208396

Change-Id: Ia0c095d1b0b202e99991aabdf96e12b52c922c5c
Merge "Fix sphinx error in swift.common.utils"