Linux: install_session_keyring: key_alloc flags are unsigned long

Linux: install_session_keyring: key_alloc flags are unsigned long

Signed-off-by: Anders Kaseorg <andersk@mit.edu>
Reviewed-on: http://gerrit.openafs.org/4034
Reviewed-by: Marc Dionne <marc.c.dionne@gmail.com>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementia.org>
(cherry picked from commit 559152ac107f91c8c2f11a909ef638551227b04a)

Change-Id: I72b8d28b27114afb9bc25d4c8d6abe5a1daf34dd
Signed-off-by: Anders Kaseorg <andersk@mit.edu>
Reviewed-on: http://gerrit.openafs.org/4055
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementia.org>