core: adding code to run pre-upgrade scripts
core: adding code to run pre-upgrade scripts

Adding code to run all sql files under pre_upgrade before all other upgrade/*.sql scripts

Change-Id: I3c81e40eb5ce527761ceeaf1562d9af076e7eaeb

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