Fix bug 2231: reverse_sync in fsmongo obtains file timestamp with UTC timezone...

Fix bug 2231: reverse_sync in fsmongo obtains file timestamp with UTC timezone instead of local timezone, so
that filesystem and mongodb timestamps are correctly compared

Change-Id: I0056026704a624329aae1ae52a45143d12f6dfdd
Signed-off-by: Gabriel Cuba <gcuba@whitestack.com>
(cherry picked from commit 09496abf)