cxmanage: Warn when updating firmware without --all-nodes
cxmanage: Warn when updating firmware without --all-nodes

This requires the user to specify "y" or "yes" to continue.

SilverLiningSystems/cxmanage-test2,SilverLiningSystems/cxmanage-test,SLS-Dev/cxmanage,SLS-Dev/cxmanage,Cynerva/cxmanage,Cynerva/cxmanage,SilverLiningSystems/cxmanage-test,SilverLiningSystems/cxmanage-test2