LU-11272 lnet: router handling

LU-11272 lnet: router handling

Re-create the md and mdh if the router checker ping times out.
When re-transmitting a message do so even if the peer is marked down
to fulfill the message's retry quota.

Test-Parameters: trivial
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: I7b2a1ec6602dac9a112f4d318b0512f68f923969
Reviewed-on: https://review.whamcloud.com/33043
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Olaf Weber <olaf.weber@hpe.com>
Reviewed-by: Sonia Sharma <sharmaso@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>