LU-10800 lnet: reduce discovery timeout

Discovery protocol sends a ping (GET) to the peer and expects a
REPLY back with the interface information. Discovery uses the
DEFAULT_PEER_TIMEOUT which 180s. This could lead to extended delay
during mounting if the OSTs are down or if the ping fails for
any reason.

This patch adds a module parameter lnet_transaction_timeout which
defaults to 5 seconds. lnet_transaction_timeout is used for the
discovery timeout.

Test-Parameters: trivial
Signed-off-by: Amir Shehata <amir.shehata@intel.com>
Change-Id: Ida1e19f55552b24e83c8094aa88a37c2748126cf
Reviewed-on: https://review.whamcloud.com/31663


Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Sonia Sharma <sonia.sharma@intel.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>