Make static string literal in svnserve message gettext friendly

* subversion/svnserve/svnserve.c
  (svnserve__options): Remove use of nested macro for default port.
  Breaks scanner and cannot be printf'ed in a static definition of
  a apr_getopt_option_t[]. From r1334953/r1335021.

Approved by: stsp


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1436808 13f79535-47bb-0310-9956-ffa450edef68