Don't fall off the end of perl functions

This complies with the perlcritic policy
Subroutines::RequireFinalReturn, which is a severity 4 policy. Since we
only currently check at severity level 5, the policy is raised to that
level until we move to level 4 or lower, so that any new infringements
will be caught.

A small cosmetic piece of tidying of the pgperlcritic script is
included.

Mike Blackwell

Discussion: https://postgr.es/m/CAESHdJpfFm_9wQnQ3koY3c91FoRQsO-fh02za9R3OEMndOn84A@mail.gmail.com

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

@@ -53,6 +53,7 @@ template1
 	}
 
 	RewindTest::clean_rewind_test();
+	return;
 }
 
 # Run the test in both modes.