os/bluestore: cap omap naming scheme upgrade transactoin.

os/bluestore: cap omap naming scheme upgrade transactoin.

We shouldn't use single per-onode transaction for such an upgrade when onode's omap list is huge. This results in similarly sized WAL/SST files which are inefficient, might cause high memory usage and sometimes error-prone.

Fixes: https://tracker.ceph.com/issues/49170
Signed-off-by: Igor Fedotov <ifedotov@suse.com>
(cherry picked from commit e897fa243c1dd38329733b452872616023f14ac8)

 Conflicts (caused by lack of per-pg omap scheme):
	src/os/bluestore/BlueStore.cc
	src/os/bluestore/BlueStore.h
	src/os/bluestore/bluestore_types.h