BUG: Use KWStyle's GCC-style output for pre-commit style check

The GCC-style output is less confusing for humans to read, and is
consistent with the test that the dashboard will run.

Change-Id: I2fcf83a157000196df12ff9d2a97939d0a050c9a
Merge topic 'Precommit-KWStyle'

5fd862c BUG: Use KWStyle's GCC-style output for pre-commit style check