Use real names for page lock operations

Use real names for page lock operations

Call a spade a spade. Don't use macros to rename lock_page as LockPage,
and unlock_page as UnlockPage. Instead use the same names as the kernel,
which makes it a lot easier for people familiar with kernel code to read
ours.

Reviewed-on: http://gerrit.openafs.org/692
Reviewed-by: Marc Dionne <marc.c.dionne@gmail.com>
Tested-by: Derrick Brashear <shadow@dementia.org>
Reviewed-by: Derrick Brashear <shadow@dementia.org>