test: minor case fix

Signed-off-by: Loic Dachary <loic-201408@dachary.org>
(cherry picked from commit 6f698374562de74806203c7b41072572b59bd256)
mon: obsolete osdmonitor_prepare_command

And the mon_advanced_debug_mode option that is only used in the context
of osdmonitor_prepare_command.

http://tracker.ceph.com/issues/9245 Fixes: #9245

Signed-off-by: Loic Dachary <loic-201408@dachary.org>
(cherry picked from commit 2abc8f400f7db256c2a30f1d0886a593e6c194eb)
tests: remove tests requiring osdmonitor_prepare_command

Although they have been useful, their maintenance and fragility caused
more trouble than their benefits.

Signed-off-by: Loic Dachary <loic-201408@dachary.org>
(cherry picked from commit 038de0031bc0892359201012dafb82ac1b1a4d0f)
Merge pull request #2637 from dachary/wip-9245-test-mon-pending-giant

mon: obsolete osdmonitor_prepare_command (giant)