Add rebuild action descriptions in support-matrix
Add rebuild action descriptions in support-matrix

Currently the rebuild action is supported in API and CLI of nova
though only ironic driver has its own implementation, we can still
list it into the support matix to provide more info to user.

Change-Id: I391b54a383501d3cdd2ac799d0ce4ccf66243f5a

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