afs: increase idledead time

afs: increase idledead time

it's actually important this be more than the rx call dead time
so timing out server callbacks to clients don't result in us idle deading
a call to the server when callbacks need to be broken

FIXES 130327

Reviewed-on: http://gerrit.openafs.org/6497
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementix.org>
(cherry picked from commit 0f4da13137612a9b0c0c3b57aa939d6661fb67f8)

Change-Id: I181d89c36175be93ed59226b401d48903fb5f584
Reviewed-on: http://gerrit.openafs.org/6518
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementix.org>