Check if rpm dependencies are satisfied BEFORE build is started

Log from IRC:

18:18 < mgoldmann> so you want to check if THAT rpm is in THAT repos?
18:18 < mgoldmann> other words: if dependencies from yaml file are satisfied by packages in available repos?
18:22 <@bobmcw> dunno for sure.  I do recall having to wait through a crapload of install to find out I was somehow missing some 
            package, or had typo'd the name or somesuch
18:23 < mgoldmann> good, I ad a ticket for that
18:23 < mgoldmann> add*
18:23 <@bobmcw> I forget the exact scenario
18:23 <@bobmcw> but if it can fail during the pkg install phase, a pre-verification could be super-nice
18:24 < mgoldmann> fine, np :)