core: fixing taskcleaner.sh utility help
core: fixing taskcleaner.sh utility help

This patch fixes the -R option description to note that all tasks will
be removed unless also the -z option is given.

Change-Id: If139423d1158060b00d0c205bc94608a06e1572c
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1079469
Signed-off-by: Eli Mesika <dc8a2a200abf66067593de2e51fee9376f06ea0f@redhat.com>

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