Remove unneeded CI workarounds

Remove the nova temprevert it no longer does anything (conflict) and
doesn't appear to be needed any longer. Remove the horizon cherry-pick
a fix for this problem has been merged in
Ie57de8314df08f3353e65ba6a46f186d1d28af90.

Change-Id: I4198856fb101f5e77ed9500dcfa8791a4fe0deff
Merge "Remove unneeded CI workarounds"