Gate on certain pyflakes failures

To prevent recent gating problems from typos, an
import not used and redefinition of function problems in
the source code have become gating.

Fixes: Bug #1131275
Change-Id: I7011f3ac5940afc70c38758e67a2222a66e625c3
Signed-off-by: Steven Dake <sdake@redhat.com>

tools/pyflakes-bypass.py

@@ -0,0 +1,15 @@
+from pyflakes.scripts import pyflakes
+from pyflakes.checker import Checker
+
+
+def report_with_bypass(self, messageClass, *args, **kwargs):
+    text_lineno = args[0] - 1
+    with open(self.filename, 'r') as code:
+        if code.readlines()[text_lineno].find('pyflakes_bypass') >= 0:
+            return
+    self.messages.append(messageClass(self.filename, *args, **kwargs))
+
+# monkey patch checker to support bypass
+Checker.report = report_with_bypass
+
+pyflakes.main()

tools/run_pep8.sh

@@ -15,3 +15,6 @@ ${PEP8} ${EXCLUDE} .
 
 # Check binaries without py extension
 ${PEP8} bin/heat-api bin/heat-api-cfn bin/heat-api-cloudwatch bin/heat-cfn bin/heat-engine bin/heat-watch
+
+! python tools/pyflakes-bypass.py heat/ | grep "imported but unused\|redefinition of function"
+