osd rados command: list-inconsistent-obj attribute improvements

osd rados command: list-inconsistent-obj attribute improvements

System attributes shown as "object_info", "snapset" and "hashinfo"
Only output user attributes as "attrs"
	Drop leading undescore "_" for user attribute keys
Improve logic as to when to show user attributes or specific system attributes

Signed-off-by: David Zafman <dzafman@redhat.com>
(cherry picked from commit 982509514c0c990dcdf7f35725dece61714bfa59)

Conflicts:
	qa/standalone/scrub/osd-scrub-repair.sh (trivial)
	src/osd/osd_types.cc (trivial)
	src/tools/rados/rados.cc (uses ::decode())