[GFS2] Fix setting of inherit jdata attr

Due to a mix up between the jdata attribute and inherit jdata attribute
it has not been possible to set the inherit jdata attribute on
directories. This is now fixed and the ioctl will report the inherit
jdata attribute for directories rather than the jdata attribute as it
did previously. This stems from our need to have the one bit in the
ioctl attr flags mean two different things according to whether the
underlying inode is a directory or not.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>