Fix the subversion version check in FSX tests.
Fix the subversion version check in FSX tests.

* subversion/tests/libsvn_fs_x/fs-x-pack-test.c
  (file_hint_at_shard_boundary,
   test_info,
   test_reps): FSX is available in 1.9+ but not 1.8-

Found by: danielsh

git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@1513012 13f79535-47bb-0310-9956-ffa450edef68

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