qemu: fix uninitialized variable warning
qemu: fix uninitialized variable warning

This commit fixes
qemu/qemu_driver.c: In function 'qemuDomainModifyDeviceFlags':
qemu/qemu_driver.c:4041:8: warning: 'ret' may be used uninitialized in this
function [-Wuninitialized]
qemu/qemu_driver.c:4013:9: note: 'ret' was declared here

The variable is set to -1 so that the error paths are taken when the code
to set it didn't get a chance to run. Without initializing it, we could
return some an undefined value from this function.

While I was at it, I made a trivial whitespace change in the same function
to improve readability.

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