Shut down test servers after pg_rewind regression tests.

Now that the test servers are initialized twice in each .pl script,
the single END block is not enough to stop them. Add a new clean_rewind_test
function that is called at the end of each test.

Michael Paquier

src/bin/pg_rewind/t/002_databases.pl

@@ -40,6 +40,7 @@ standby_afterpromotion
 ),
 			   'database names');
 
+	RewindTest::clean_rewind_test();
 }
 
 # Run the test in both modes.