Rx: Treat rx_minPeerTimeout not as a minimum but as padding

Rx: Treat rx_minPeerTimeout not as a minimum but as padding

An improved RTT and timeout calculation algorithm is being
developed but until we have it, treat rx_minPeerTimeout not as
a minimum value for the timeout but as padding to be added to
the measured RTT when computing the peer timeout value.

With this change rx does not begin to send large numbers of
resends when the RTT begins to exceed the rx_minPeerTimeout
value.  Timeout triggered resends at the moment can force rx
into fast recovery mode which in turn kills performance.  It
is better to avoid that problem for now.

Reviewed-on: http://gerrit.openafs.org/3026
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Tested-by: Jeffrey Altman <jaltman@openafs.org>
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>
(cherry picked from commit 5c8981e0404287f2aa46390d3a9e8a52261906ab)
Change-Id: I82cf73cc8153d9aba669dc581231a88949b6ec4d
Reviewed-on: http://gerrit.openafs.org/3126
Tested-by: Derrick Brashear <shadow@dementia.org>