JFS: fix memleak in jfs_mount

In jfs_mount, when diMount(ipaimap2) fails, it goes to errout35. However,
the following code does not free ipaimap2 allocated by diReadSpecial.

Fix this by refactoring the error handling code of jfs_mount. To be
specific, modify the lable name and free ipaimap2 when the above error
ocurrs.

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>