LU-4423 mdc: use 64-bit timestamps for mdc

These three are timestamps that are sent over the wire in mdc_lib
and the obd logging 64-bit values, but are generated using the 32-bit
get_seconds() function, which will eventually overflow.

Changing them to use 64-bit ktime_get_real_seconds() solves the problem.

Linux-commit: 14e3f92a4c46eedfe745b0dec42a4dcb1b16a989

Change-Id: I2063ae51a8335cd6887f800f0f30e8d90cfe7d2b
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-on: https://review.whamcloud.com/25405
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Mike Pershin <mike.pershin@intel.com>
Reviewed-by: Fan Yong <fan.yong@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>