ReplicatedPG: check store for temp collection in have_temp_coll

We may not have "created" the temp collection since OSD restart
before removing the PG.  have_temp_coll must also look at the
OSD store.  Currently, the only user is pg removal, so the
extra work is acceptable.

Backport: bobtail
Signed-off-by: Samuel Just <sam.just@inktank.com>