Linux 3.7: key instantiate API change

Linux 3.7: key instantiate API change

Adapt to the new parameters for the instantiate key operation.

Reviewed-on: http://gerrit.openafs.org/8470
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Hans-Werner Paulsen <hans@MPA-Garching.MPG.DE>
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>
(cherry picked from commit aeb2763b741a218ad6fd93adc6157a6a31f27e13)

Change-Id: I9ff22683aaf6e1002bdb2bc7666fbc0d8d597d20
Reviewed-on: http://gerrit.openafs.org/8560
Reviewed-by: Ken Dreyer <ktdreyer@ktdreyer.com>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>
Reviewed-by: Paul Smeddle <paul.smeddle@gmail.com>