[XFS] clean up xfs_swapext
[XFS] clean up xfs_swapext

- stop using vnodes
- use proper multiple label goto unwinding
- give the struct file * variables saner names

SGI-PV: 971186
SGI-Modid: xfs-linux-melb:xfs-kern:30366a

Signed-off-by: Christoph Hellwig <923f7720577207a44b32e59bbfbea59d27f1ae8e@infradead.org>
Signed-off-by: Lachlan McIlroy <f5e96ceb240f4c6b121fe0445b266d7666b5fe0e@sgi.com>

TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs