|WARNING| pw136221 [PATCH v2] doc: update guideline for fix commit messages

[checkpatch at dpdk.org]

Test-Label: checkpatch
Test-Status: WARNING
http://dpdk.org/patch/136221

_coding style issues_


WARNING:BAD_SIGN_OFF: Do not use whitespace before Signed-off-by:
#88: FILE: doc/guides/contributing/patches.rst:275:
      Signed-off-by: Alex Smith <alex.smith at example.com>

total: 0 errors, 1 warnings, 11 lines checked