Ironic's grenade multinode suffers from some of unique issues.
* Nova can never be upgraded as there is a static pin that increments
higher. As such, newer nova can never run with older ironic.
* As Nova cannot be upgraded, it is left running throughout the test
sequence.
The above two conditions result in possible breaking package upgrades
as the python environments are shared between the old and new
installations.
In order to better isolate the running processes, as would be in
most actual production environments, we need to minimize underlying
inter-reactions due to python library upgrades.
Credit goes to Jim Rollenhagen for coming up with this idea, once the
massive conundrum was fully explained. Thanks Jim!
Partial-Bug: #1744139
Change-Id: Ifdd119d9cdde2ead6c3e36862cc77da67d10f7d1
(cherry picked from commit 93f376f345)
780ab207a1