libvirtd: start each diagnostic with "argv0: "
libvirtd: start each diagnostic with "argv0: "

Some diagnostics had a hard-coded "libvirtd: " prefix, some used
"error: " and some used "argv[0]: ".  Always use "argv[0]: ".
* daemon/libvirtd.c (argv0): New global.
(main): Set it.
(version, usage): Remove argv0 parameter.  Use global; update callers.
(daemonForkIntoBackground): Use argv0:, not error:.
(qemudWritePidFile): Start each diagnostic with argv0:.
Suggested by Eric Blake.

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