network: Fix NULL dereference during error recovery
network: Fix NULL dereference during error recovery

This fixes: https://bugzilla.redhat.com/show_bug.cgi?id=696660

While starting a network, if brSetForwardDelay() fails, we go to err1
where we want to access macTapIfName variable which was just
VIR_FREE'd a few lines above. Instead, keep macTapIfName until we are
certain of success.

novel/fbsd-libvirt,leilihh/libvirt,trainstack/libvirt,VenkatDatta/libvirt,soulxu/libvirt-xuhj,siboulet/libvirt-openvz,zhlcindy/libvirt-1.1.4-maintain,olafhering/libvirt,shugaoye/libvirt,novel/fbsd-libvirt,iam-TJ/libvirt,leilihh/libvirt,jeckersb/libvirt,trainstack/libvirt,eskultety/libvirt,wiedi/libvirt,bjzhang/libvirt,rmarwaha/libvirt,soulxu/libvirt-xuhj,jardasgit/libvirt,jfehlig/libvirt,trainstack/libvirt,taget/libvirt,emaste/libvirt,libvirt/libvirt,andreabolognani/libvirt,shugaoye/libvirt,dumbbell/libvirt,emaste/libvirt,rmarwaha/libvirt1,wiedi/libvirt,novel/fbsd-libvirt,rmarwaha/libvirt1,jeckersb/libvirt,trainstack/libvirt,warewolf/libvirt,trainstack/libvirt,foomango/libvirt,andreabolognani/libvirt,jeckersb/libvirt,VenkatDatta/libvirt,taget/libvirt,nertpinx/libvirt,dumbbell/libvirt,crobinso/libvirt,novel/fbsd-libvirt,jfehlig/libvirt,rlaager/libvirt,soulxu/libvirt-xuhj,jardasgit/libvirt,nertpinx/libvirt,olafhering/libvirt,trainstack/libvirt,fabianfreyer/libvirt,rlaager/libvirt,rmarwaha/libvirt,kantai/libvirt-vfork,shugaoye/libvirt,soulxu/libvirt-xuhj,leilihh/libvirt,agx/libvirt,jeckersb/libvirt,warewolf/libvirt,siboulet/libvirt-openvz,nertpinx/libvirt,agx/libvirt,cbosdo/libvirt,jeckersb/libvirt,zippy2/libvirt,iam-TJ/libvirt,rmarwaha/libvirt,novel/fbsd-libvirt,cbosdo/libvirt,emaste/libvirt,zhlcindy/libvirt-1.1.4-maintain,olafhering/libvirt,kantai/libvirt-vfork,zhlcindy/libvirt-1.1.4-maintain,soulxu/libvirt-xuhj,libvirt/libvirt,dumbbell/libvirt,bjzhang/libvirt,rmarwaha/libvirt1,nertpinx/libvirt,siboulet/libvirt-openvz,rmarwaha/libvirt1,warewolf/libvirt,cbosdo/libvirt,libvirt/libvirt,iam-TJ/libvirt,novel/fbsd-libvirt,eskultety/libvirt,emaste/libvirt,leilihh/libvirt,foomango/libvirt,taget/libvirt,leilihh/libvirt,rlaager/libvirt,rmarwaha/libvirt,dumbbell/libvirt,datto/libvirt,usc-isi/libvirt,taget/libvirt,foomango/libvirt,VenkatDatta/libvirt,eskultety/libvirt,danwent/libvirt-ovs,andreabolognani/libvirt,libvirt/libvirt,elmarco/libvirt,crobinso/libvirt,warewolf/libvirt,novel/fbsd-libvirt,novel/fbsd-libvirt,iam-TJ/libvirt,elmarco/libvirt,wiedi/libvirt,zippy2/libvirt,usc-isi/libvirt,elmarco/libvirt,siboulet/libvirt-openvz,kantai/libvirt-vfork,andreabolognani/libvirt,shugaoye/libvirt,jeckersb/libvirt,shugaoye/libvirt,fabianfreyer/libvirt,dumbbell/libvirt,emaste/libvirt,warewolf/libvirt,trainstack/libvirt,wiedi/libvirt,jardasgit/libvirt,jardasgit/libvirt,jardasgit/libvirt,danwent/libvirt-ovs,datto/libvirt,wiedi/libvirt,iam-TJ/libvirt,iam-TJ/libvirt,siboulet/libvirt-openvz,fabianfreyer/libvirt,taget/libvirt,bjzhang/libvirt,crobinso/libvirt,VenkatDatta/libvirt,rmarwaha/libvirt,nertpinx/libvirt,leilihh/libvirt,andreabolognani/libvirt,eskultety/libvirt,warewolf/libvirt,fabianfreyer/libvirt,danwent/libvirt-ovs,VenkatDatta/libvirt,agx/libvirt,emaste/libvirt,novel/fbsd-libvirt,datto/libvirt,crobinso/libvirt,cbosdo/libvirt,datto/libvirt,jfehlig/libvirt,dumbbell/libvirt,bjzhang/libvirt,danwent/libvirt-ovs,elmarco/libvirt,zippy2/libvirt,datto/libvirt,foomango/libvirt,kantai/libvirt-vfork,agx/libvirt,jfehlig/libvirt,rmarwaha/libvirt1,agx/libvirt,rlaager/libvirt,zippy2/libvirt,rmarwaha/libvirt1,rlaager/libvirt,danwent/libvirt-ovs,iam-TJ/libvirt,wiedi/libvirt,elmarco/libvirt,kantai/libvirt-vfork,fabianfreyer/libvirt,olafhering/libvirt,rmarwaha/libvirt,foomango/libvirt,usc-isi/libvirt,cbosdo/libvirt,zhlcindy/libvirt-1.1.4-maintain,emaste/libvirt,wiedi/libvirt,bjzhang/libvirt,usc-isi/libvirt,eskultety/libvirt,usc-isi/libvirt,jeckersb/libvirt,zhlcindy/libvirt-1.1.4-maintain,warewolf/libvirt