Improve the help text for compute timeout_opts
Improve the help text for compute timeout_opts

Implements blueprint centralize-config-options-newton

Change-Id: I784b6569643f3f8fe4f386a2990a9b7cd54617ab

openstack/nova,gooddata/openstack-nova,cloudbase/nova,jianghuaw/nova,vmturbo/nova,jianghuaw/nova,hanlind/nova,rajalokan/nova,gooddata/openstack-nova,gooddata/openstack-nova,alaski/nova,mikalstill/nova,sebrandon1/nova,mahak/nova,jianghuaw/nova,rahulunair/nova,phenoxim/nova,Juniper/nova,rajalokan/nova,cloudbase/nova,klmitch/nova,jianghuaw/nova,cloudbase/nova,klmitch/nova,mahak/nova,sebrandon1/nova,rajalokan/nova,mahak/nova,hanlind/nova,mikalstill/nova,mikalstill/nova,hanlind/nova,rajalokan/nova,klmitch/nova,Juniper/nova,phenoxim/nova,klmitch/nova,alaski/nova,vmturbo/nova,gooddata/openstack-nova,rahulunair/nova,openstack/nova,sebrandon1/nova,openstack/nova,vmturbo/nova,Juniper/nova,Juniper/nova,rahulunair/nova,vmturbo/nova