Minor test adjustment.

Dept of second thoughts: given the RESET SESSION AUTHORIZATION that
was just added by commit cec5501, we don't need the reconnection
that used to be here.  Might as well buy back a few microseconds.

Author: tglsfdc

src/test/regress/expected/cluster.out

@@ -474,7 +474,6 @@ reset enable_indexscan;
 reset maintenance_work_mem;
 reset replacement_sort_tuples;
 -- clean up
-\c -
 DROP TABLE clustertest;
 DROP TABLE clstr_1;
 DROP TABLE clstr_2;

src/test/regress/sql/cluster.sql

@@ -228,7 +228,6 @@ reset maintenance_work_mem;
 reset replacement_sort_tuples;
 
 -- clean up
-\c -
 DROP TABLE clustertest;
 DROP TABLE clstr_1;
 DROP TABLE clstr_2;