Log warning when user set improper config option value
Log warning when user set improper config option value

User may set wrong values for live migration related config options,
log warning when setting with wrong values, will use parameter min
of IntOpt to enforce these config options' values in Pike.

Change-Id: I064958998939da3e05bd04631a36d2a507bf50c1

klmitch/nova,gooddata/openstack-nova,vmturbo/nova,mikalstill/nova,openstack/nova,hanlind/nova,rahulunair/nova,klmitch/nova,mikalstill/nova,klmitch/nova,rajalokan/nova,rahulunair/nova,Juniper/nova,rajalokan/nova,Juniper/nova,jianghuaw/nova,phenoxim/nova,mahak/nova,jianghuaw/nova,jianghuaw/nova,vmturbo/nova,gooddata/openstack-nova,openstack/nova,Juniper/nova,rajalokan/nova,rajalokan/nova,mahak/nova,Juniper/nova,jianghuaw/nova,gooddata/openstack-nova,klmitch/nova,phenoxim/nova,hanlind/nova,mikalstill/nova,vmturbo/nova,vmturbo/nova,gooddata/openstack-nova,openstack/nova,mahak/nova,hanlind/nova,rahulunair/nova