Improve readability.  No functional change.

* subversion/svnserve/svnserve.c
  (release_connection_pool): Whitespace change only.

Suggested by: rhuijben

git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1523480 13f79535-47bb-0310-9956-ffa450edef68