Avoid initializing svn_fs_id_t parts with pointers to stack variables, which
will eventually become dangling.  Follow-up to r1506545.

* subversion/libsvn_fs_fs/id.c
  (svn_fs_fs__id_txn_create_root, svn_fs_fs__id_create_root,
   svn_fs_fs__id_txn_create, svn_fs_fs__id_rev_create, svn_fs_fs__id_parse):
   Fix the erroneous FSAP_DATA initialization with an address of a temporary.

Patch by: Evgeny Kotkov <evgeny.kotkov{_AT_}visualsvn.com>