Start using Pyflakes and Hacking

Instead of globally ignoring pyflakes and
hacking warnings, only blacklist those that trigger
very frequently so far, in order to clean them
up in followup commits. Fix and start gating
on the rest already.

Change-Id: Ied7c7250061e3bf379e8286e8ce3b9e4af817faf

run_tests.sh

@@ -4,13 +4,13 @@ function usage {
   echo "Usage: $0 [OPTION]..."
   echo "Run python-glanceclient's test suite(s)"
   echo ""
-  echo "  -p, --pep8               Just run pep8"
+  echo "  -p, --pep8               Just run flake8"
   echo "  -h, --help               Print this usage message"
   echo ""
   echo "This script is deprecated and currently retained for compatibility."
   echo 'You can run the full test suite for multiple environments by running "tox".'
   echo 'You can run tests for only python 2.7 by running "tox -e py27", or run only'
-  echo 'the pep8 tests with "tox -e pep8".'
+  echo 'the flake8 tests with "tox -e pep8".'
   exit
 }