util: report the MAC address that couldn't be set
util: report the MAC address that couldn't be set

I noticed in a log file that we had failed to set a MAC address. The
log said which interface we were trying to set, but didn't give the
offending MAC address, which could have been useful in determining the
source of the problem. This patch modifies all three places in the
code that set MAC addresses to report the failed MAC as well as
interface.

jfehlig/libvirt,jardasgit/libvirt,libvirt/libvirt,rlaager/libvirt,datto/libvirt,rlaager/libvirt,eskultety/libvirt,eskultety/libvirt,jfehlig/libvirt,rlaager/libvirt,fabianfreyer/libvirt,taget/libvirt,zippy2/libvirt,datto/libvirt,libvirt/libvirt,zippy2/libvirt,nertpinx/libvirt,VenkatDatta/libvirt,nertpinx/libvirt,crobinso/libvirt,VenkatDatta/libvirt,fabianfreyer/libvirt,jardasgit/libvirt,andreabolognani/libvirt,olafhering/libvirt,datto/libvirt,crobinso/libvirt,jfehlig/libvirt,jardasgit/libvirt,jardasgit/libvirt,jardasgit/libvirt,eskultety/libvirt,taget/libvirt,crobinso/libvirt,olafhering/libvirt,rlaager/libvirt,libvirt/libvirt,zippy2/libvirt,libvirt/libvirt,eskultety/libvirt,jfehlig/libvirt,zippy2/libvirt,andreabolognani/libvirt,andreabolognani/libvirt,VenkatDatta/libvirt,taget/libvirt,andreabolognani/libvirt,fabianfreyer/libvirt,fabianfreyer/libvirt,datto/libvirt,taget/libvirt,rlaager/libvirt,olafhering/libvirt,fabianfreyer/libvirt,VenkatDatta/libvirt,taget/libvirt,VenkatDatta/libvirt,eskultety/libvirt,nertpinx/libvirt,andreabolognani/libvirt,nertpinx/libvirt,olafhering/libvirt,datto/libvirt,crobinso/libvirt,nertpinx/libvirt