build: fix compilation on mingw
build: fix compilation on mingw

* src/util/command.c (virCommandAbort) [WIN32]: Provide stub.
Reported by Daniel P. Berrange's autobuilder.

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