libext2fs: ext2fs_[set_]file_acl_block needs to check for 64-bit feature flag

libext2fs: ext2fs_[set_]file_acl_block needs to check for 64-bit feature flag

The ext2fs_file_acl_block() and ext2fs_set_file_acl_block() needs to
only check i_file_acl_high if the 64-bit flag is set.  This is needed
because otherwise we will run into problems on Hurd systems which
actually use that field for h_i_mode_high.

This involves an ABI change since we need to pass ext2_filsys to these
functions.  Fortunately these functions were first included in the
1.42-WIP series, so it's OK for us to change them now.  (This is why
we have 1.42-WIP releases.  :-)

Addresses-Sourceforge-Bug: #3379227

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>