RX: Force sane timeout values

RX: Force sane timeout values

Currently we do not check the specified timeout values when someone
changes a connection's dead, idle, or hard dead time. However, if the
conn's dead time is larger than the other two times, a loss of network
activity will result in one of the other timeouts getting triggered
first.

To prevent this and possibly other problems from happening, force a
connection's timeouts to always obey the relationship
secondsUntilDead <= idleDeadTime <= hardDeadTime, by checking these
values whenever they are changed.

Change-Id: I681dce7f359bf71333e69ceab8186bdc1d54d8dc
Reviewed-on: http://gerrit.openafs.org/2947
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>
Tested-by: Jeffrey Altman <jaltman@openafs.org>