gfs2: Fix error path kobject memory leak

If a call to kobject_init_and_add() fails we must call kobject_put()
otherwise we leak memory.

Function gfs2_sys_fs_add always calls kobject_init_and_add() which
always calls kobject_init().

It is safe to leave object destruction up to the kobject release
function and never free it manually.

Remove call to kfree() and always call kobject_put() in the error path.

Signed-off-by: Tobin C. Harding <tobin@kernel.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>