db: functions: remove unused pg_version
db: functions: remove unused pg_version

more than it is unused it checks only for client side libraries version,
which is incorrect.

Change-Id: I5ee352658a00ab7efd935060b002bce96875eda1
Signed-off-by: Alon Bar-Lev <2e3ceb4d37adc6ae3ccc00d3646e0e0a036ace03@redhat.com>

walteryang47/ovirt-engine,zerodengxinchao/ovirt-engine,halober/ovirt-engine,yapengsong/ovirt-engine,yingyun001/ovirt-engine,walteryang47/ovirt-engine,halober/ovirt-engine,yapengsong/ovirt-engine,yapengsong/ovirt-engine,yingyun001/ovirt-engine,OpenUniversity/ovirt-engine,walteryang47/ovirt-engine,eayun/ovirt-engine,yingyun001/ovirt-engine,yingyun001/ovirt-engine,zerodengxinchao/ovirt-engine,eayun/ovirt-engine,yapengsong/ovirt-engine,yapengsong/ovirt-engine,walteryang47/ovirt-engine,eayun/ovirt-engine,eayun/ovirt-engine,yingyun001/ovirt-engine,zerodengxinchao/ovirt-engine,zerodengxinchao/ovirt-engine,halober/ovirt-engine,OpenUniversity/ovirt-engine,OpenUniversity/ovirt-engine,eayun/ovirt-engine,walteryang47/ovirt-engine,OpenUniversity/ovirt-engine,zerodengxinchao/ovirt-engine,halober/ovirt-engine,OpenUniversity/ovirt-engine