Fix compiler warning in FSFS C tests.

* subversion/tests/libsvn-fs_fs/fs-fs-pack-test.c
  (created_packed_filesystem, prepare_revprop_repo): Use svn_revnum_t
    consistently for revision numbers.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1570338 13f79535-47bb-0310-9956-ffa450edef68