errcode is typedef by mingw, rename an argument name
errcode is typedef by mingw, rename an argument name

Fixes the following warning:
util/virterror.c:1242:31: warning: declaration of 'errcode' shadows a global declaration [-Wshadow]

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