Improve Ironic driver performance: patch 6

As part of some large scale operational testing, some needed
performance improvements in the ironic driver have been
identified.  These changes have been reviewed and have been
merged into the ironic tree previously (reviews 108545 & 113036)

Change-Id: I635b974353a9dee542739857aa9778bf1e78cca8
Co-authored-by: Jim Rollenhagen <jim@jimrollenhagen.com>
Co-authored-by: Chris Behrens <cbehrens@codestud.com>
Merge "Improve Ironic driver performance: patch 6"