no way to delete valid/invalid security rule

Previously deleting valid/invalid security
group rules was throwing the error of
"AttributeError". With this fix, now both
types of security group rules can be deleted.

Change-Id: I253c2742efe69ee41976c88ca2775189bc5bde0d
Closes-Bug: #1163469
Remove E12* from list of deliberately ignored flake8 rules

I367064ecaa6d1fd9d918f7ce003303e2db660647  Added E12 to the
ignored on purpose list, which also makes no sense E12 was never meant
to be skipped all together (I was the one who added E12 to the flake8
ignore list (Ifc8924914b5a0d625bc8df6442ee85eb21459cde)

Then I4cf246e3ec932ba0d2391eb8bcb793b28b005b4c came along and updated
the list to break out the E12 ignored on purpose list.

Drop all E12 rules from the ignored on purpose list, as we do not want
to ignore these on purpose.

Change-Id: Ic400047347a82aebbc0f6ce6f5061e7757a02d3d
Add missing parameters for server rescue

The server rescue call supports passing a password and an image,
however novaclient does not have options to support this. This commit
adds these options and updates the related unit tests to support the
change.

Change-Id: I14c878c0027f8206671ee001ba5195f94f842314
Merge "Add missing parameters for server rescue"
Merge "Remove E12* from list of deliberately ignored flake8 rules"