Fix flake 3.6.0 warnings

flake 3.6.0 introduces a couple of new tests, handle them in the zuul
base:

* Disable "W504 line break after binary operator", this is a new warning
  with different coding style.
* Fix "F841 local variable 'e' is assigned to but never used"
* Fix "W605 invalid escape sequence" - use raw strings for regexes.
* Fix "F901 'raise NotImplemented' should be 'raise
  NotImplementedError'"
* Ignore "E252 missing whitespace around parameter equals" since it
  reports on parameters like:
  def makeNewJobs(self, old_job, parent: Job=None):

Change "flake8: noqa" to "noqa" since "flake8: noqa" is a file level
noqa and gets ignored with flake 3.6.0 if it's not at beginning of line
- this results in many warnings for files ./zuul/driver/bubblewrap/__init__.py and
./zuul/cmd/migrate.py. Fix any issues there.

Change-Id: Ia79bbc8ac0cd8e4819f61bda0091f4398464c5dc

1 files changed, 1 insertions, 1 deletions

diff --git a/test-requirements.txt b/test-requirements.txt
index 3c45caecf..2aad38abd 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -1,4 +1,4 @@
-flake8<3.6.0
+flake8
 
 coverage>=3.6
 sphinx>=1.6.1