this is followup to I2aa34cf142c6429a7a0a3b8f232c3ed83f7d9981
In order to support discovery of instances booted before Wallaby,
ceilometer must support working with both 1.0 (old, Victoria and before)
and 1.1 (new, Wallaby and for now newer) versions of nova metadata.
Conflicts: ceilometer/compute/discovery.py
Change-Id: I93b6e92a5f46de5486f30a99fa3917a5932f7360
Related-Bug: #1930446
(cherry picked from commit 2fc72043d3)
(cherry picked from commit c724307a08)