timedated: Send error when time set is past build date time

timedated: Send error when time set is past build date time

When the user/customer sets the time on the system which is prior
than that of the systemd build time, as systemd doesn't allow time
before it's build date after a reboot, systemd is resetting it but
there is no error or exception present in the setTime method due
to which user/customer is unaware of why the time is reset back to
the systemd-build time.

Added a condition check in the set_time() method to return an
error when tried to set time past the systemd build date.

Tested: Verified that it throws an error when we try to set the
time prior to systemd build date.

Change-Id: Ia6b58320bdb7234a21885a44af8fd3bda64c3789