LU-9019 osc: migrate to time64_t

LU-9019 osc: migrate to time64_t

Change od_contention_time from int to time64_t to make it clear
this field is in units of seconds. With this change move the other
*_contention_time fields from jiffies to time64_t to avoid the
overhead of switching between the two different time formats.
Change ops_submit_time also to time64_t since using jiffies
doesn't gain us anything and having it in time64_t makes it clear
this is code related to time.

Change-Id: I97d3685ac61781e6b1dc8634bc105bb0ffe76aa0
Signed-off-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-on: https://review.whamcloud.com/30063
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>