Un-break the test for issue #4481. A follow-up to r1580867.

* subversion/tests/cmdline/merge_automatic_tests.py
  (reintegrate_subtree_not_updated): Remove a spurious 'return' statement.

git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1580872 13f79535-47bb-0310-9956-ffa450edef68