On fsfs-improvements branch, followup to r1506622.

* subversion/libsvn_fs_fs/low_level.c
  (svn_fs_fs__unparse_representation): Remove redundant #undef.


git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/fsfs-improvements@1510996 13f79535-47bb-0310-9956-ffa450edef68