qa/suites/upgrade: Fix/Modify upgrade tests to work with 'pacific' release.

qa/suites/upgrade: Fix/Modify upgrade tests to work with 'pacific' release.

This commit is not a cherry-pick and fixes the following issues unique to
the pacific release:
1. Fixes the nautilus-x and octopus-x upgrade tests to work with the
   pacific release by updating the post upgrade step to set the
   'require-osd-release' flag to 'pacific'. This is done by using
   '.qa/releases/pacific.yaml' for all the tests.
2. Fixed an issue in 'upgrade-mon-osd-mds.yaml' under both the
   nautilus-x/parallel, octopus-x/parallel-no-cephadm tests. The
   'wait-for-healthy' check should not be performed after all the osds
   are upgraded since the 'require-osd-release' warning comes into
   effect. This check is delayed until after the 'require-osd-release'
   flag is set to 'pacific'.

Signed-off-by: Sridhar Seshasayee <sseshasa@redhat.com>