Remove relcache entry invalidation in REFRESH MATERIALIZED VIEW.

This was added as part of the attempt to support unlogged matviews
along with a populated status.  It got missed when unlogged
support was removed pre-commit.

Noticed by Noah Misch.  Back-patched to 9.3 branch.

src/backend/commands/matview.c

@@ -764,8 +764,6 @@ refresh_by_heap_swap(Oid matviewOid, Oid OIDNewHeap)
 {
 	finish_heap_swap(matviewOid, OIDNewHeap, false, false, true, true,
 					 RecentXmin, ReadNextMultiXactId());
-
-	RelationCacheInvalidateEntry(matviewOid);
 }