Add boto special casing for param changes in 2.13

boto 2.13 has some interface changes with the get_http_connection
call which adds port as a non optional parameter *in the middle of*
existing non optional parameters. It's a special kind of incompatible
change.

We are already special casing around boto in the unit tests, lets
just do more of that if we are running on a newer version.

(cherry picked from commit 1ce493b9e4e0c381146287161ab2a3c75f1fc603)

Change-Id: I62f5d4ef5cfa5577015a521a5d161086546a4125
Co-Authored-By: Sean Dague <sdague@linux.vnet.ibm.com>
Co-Authored-By: Dan Smith <dansmith@redhat.com>
Merge branch 'stable/grizzly' of https://github.com/openstack/nova into grizzly/stable