Linux: 3.1: adapt to fsync changes

Linux: 3.1: adapt to fsync changes

The fsync file operation gets new arguments to specify a range.
Add a configure test to check for the API change.

The inode lock is also pushed down into the operation, so we need
to take it ourselves to keep the original behaviour.

Change-Id: Icf4e152ce52f2b32c99920f83a5cc3136c05d2cd
Reviewed-on: http://gerrit.openafs.org/5332
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Simon Wilkinson <sxw@inf.ed.ac.uk>
Reviewed-by: Derrick Brashear <shadow@dementix.org>