Follow-up to r1606132:

* tools/server-side/svnfsfs/load-index-cmd.c
  (write_l2p_index): Create the proto-index file in a pool that survives
                     this function - it's name is a return value.
                                   


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1606513 13f79535-47bb-0310-9956-ffa450edef68