Remove duplicate assertion segment count

There is already an assertion in getgpsegmentCount() testing the count
to be > 0 (and 0 can only be returned in utility mode which still holds
this assertion always true).
Reviewed-by: NHeikki Linnakangas <hlinnakangas@pivotal.io>
Reviewed-by: NVenkatesh Raghavan <vraghavan@pivotal.io>

src/backend/cdb/cdbcopy.c

@@ -75,8 +75,6 @@ makeCdbCopy(bool is_copy_in)
 	c->total_segs = getgpsegmentCount();
 	c->aotupcounts = NULL;
 
-	Assert(c->total_segs >= 0);
-
 	/* Initialize the state of each segment database */
 	c->segdb_state = (SegDbState **) palloc((c->total_segs) * sizeof(SegDbState *));