aoe: copy fallback timing information on destination failover

Commit f3b8e07af774 ("aoe: commands in retransmit queue use new
destination on failure") omits the copying of the coarse-grained time
when an AoE command was sent during the failover from one destination
MAC address on the AoE target to another.

The coarse-grained timing is only used when the system time changes or
an unlikely length of time has passed since the sending of the AoE
command.  Users will not be impacted unless their system clock is very
inaccurate or something unusual (e.g., 10 GbE link reset) happens during
the period when the aoe driver is handling the failure of a port on the
AoE target.  Being effected will mean that an AoE target could be
considered "down" too eagerly.

Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>