Following up on r1668323, revert regression that the session url is allocated in the wrong pool.
Following up on r1668323, revert regression that the session url is
allocated in the wrong pool.

* subversion/libsvn_ra_serf/serf.c
  (svn_ra_serf__open): Allocate uri result in session pool.


git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@1668329 13f79535-47bb-0310-9956-ffa450edef68

YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion