Remove the flake8 --repeat flag in the travis.yml file

The flake8 --repeat flag is not longer supported

Change-Id: Idaaebe8224e4d2ce03e634519e5aa74d26fe953a
Signed-off-by: Rosario Di Somma <rosario.disomma@dreamhost.com>
Merge pull request #16 from rodis/stable/folsom

Remove the flake8 --repeat flag in the travis.yml file