Follow-up to r1589048:
Fix deprecation warnings by making fs_library_vtable_t.set_svn_fs_open
functions with svn_fs_open2-compatible signatures.

* subversion/libsvn_fs/fs-loader.h
  (fs_library_vtable_t): Make set_svn_fs_open's svn_fs_open_ parameter
                         match svn_fs_open2 in signature.

* subversion/libsvn_fs_base/fs.c
  (base_set_svn_fs_open): Update function signature.

* subversion/libsvn_fs_fs/fs.c
  (fs_set_svn_fs_open): Same.

* subversion/libsvn_fs_x/fs.c
  (x_set_svn_fs_open): Same.

* subversion/libsvn_fs_fs/fs.h
  (fs_fs_data_t): Update the forwarding function pointer signature
                  to match svn_fs_open2 as well.

* subversion/libsvn_fs_x/fs.h
  (fs_x_data_t): Same.

* subversion/libsvn_fs/fs-loader.c
  (svn_fs_create,
   svn_fs_open2,
   svn_fs_create_berkeley,
   svn_fs_open_berkeley): Fix the immediate deprecation warning by
                          using svn_fs_open2 instead of svn_fs_open.

* subversion/libsvn_fs_fs/transaction.c
  (verify_as_revision_before_current_plus_plus): Update function call.

* subversion/libsvn_fs_x/transaction.c
  (verify_as_revision_before_current_plus_plus): Same.

git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1597414 13f79535-47bb-0310-9956-ffa450edef68