gfs2: Remove inode from ordered write list in gfs2_write_inode()

The vfs clears the I_DIRTY inode flag before calling gfs2_write_inode()
having queued any data that needed to be written to disk.
This is a good time to remove such inodes from our ordered write list
so they don't hang around for long periods of time.

Signed-off-by: Abhi Das <adas@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>