Destroyed OSDs awaiting replacement from osd-replacement flow should
be ignored by managed PDB to avoid the following situation:
replaced OSD is already destroyed, its deployment is downscaled zero
and it awaits the physical swap (can take days). This situation does
not trigger blocking PDB in happy case because OSD does not holds PGs.
However, if PGs go unclean during that window for an unrelated reason,
the destroyed OSD gets counted as a down OSD and can grab the single
"draining failure domain" slot - putting blocking PDBs on every other FD.
Signed-off-by: Artem Torubarov <artem.torubarov@sap.com>