LU-13510 lnet: Correct the default LND timeout

LU-13510 lnet: Correct the default LND timeout

Default LND timeout is currently too low. To allow for
lnet_retry_count resend attempts within a single
lnet_transaction_timeout window, the LND timeout needs to be less
than lnet_transaction_timeout / lnet_retry_count. If the retry
count is 0, we still want LND timeout to be less than the LNet
transaction timeout.

Also, be sure to update the LND timeout when health is toggled on or
off.

Signed-off-by: Chris Horn <hornc@cray.com>
Change-Id: Ifd6d97895192a321081aa09ebe9f1d0115e63305
Reviewed-on: https://review.whamcloud.com/38481
Reviewed-by: Serguei Smirnov <ssmirnov@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Amir Shehata <ashehata@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>