rx: handle clock reversals for call timeouts
If the clock is set backwards, call timeouts will not trigger
until the clock regains its original value plus the timeout period.
In rxi_CheckCall(), look for a backward clock shift and if one is
noticed, fail the call with RX_CALL_TIMEOUT.
Change-Id: I7ca5abee165fc21d72d3881670f9522d315b4982
Reviewed-on: http://gerrit.openafs.org/6943
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementix.org>
Tested-by: Jeffrey Altman <jaltman@secure-endpoints.com>
Reviewed-by: Jeffrey Altman <jaltman@secure-endpoints.com>