Remove dependencies on pep8, pyflakes and flake8

They should be determined by the hacking dependency
implicitely.

Change-Id: I8805f7b0ef9f2b1f59be342e9c6d032330707688
Attempt to fix periodic memcache timeout test

Not sure this will really fix the issue, but made a small change that
seemed to make more sense for the flow of the test.

Closes-Bug: #1272503
Change-Id: Ifb25ed7c4a42b11f74d865787f63fea4e0beb745
Merge "Attempt to fix periodic memcache timeout test"
Merge "Remove dependencies on pep8, pyflakes and flake8"