osd/PG: change error to dout in _scan_rollback_obs()

This message is now expected during scrubbing, since we do not delete
objects during a rollforward when !transaction_applied.

Signed-off-by: Neha Ojha <nojha@redhat.com>

src/osd/PG.cc

@@ -4589,12 +4589,12 @@ void PG::_scan_rollback_obs(const vector<ghobject_t> &rollback_obs)
        i != rollback_obs.end();
        ++i) {
     if (i->generation < trimmed_to.version) {
-      osd->clog->error() << "osd." << osd->whoami
-			<< " pg " << info.pgid
-			<< " found obsolete rollback obj "
-			<< *i << " generation < trimmed_to "
-			<< trimmed_to
-			<< "...repaired";
+      dout(10) << __func__ << "osd." << osd->whoami
+	       << " pg " << info.pgid
+	       << " found obsolete rollback obj "
+	       << *i << " generation < trimmed_to "
+	       << trimmed_to
+	       << "...repaired" << dendl;
       t.remove(coll, *i);
     }
   }