network_conf.c: Free xmlDoc after use
network_conf.c: Free xmlDoc after use

The virNetworkObjUpdateParseFile() function was not freeing the xml
variable, leaving us with a memory leak.

trainstack/libvirt,andreabolognani/libvirt,agx/libvirt,nertpinx/libvirt,siboulet/libvirt-openvz,andreabolognani/libvirt,fabianfreyer/libvirt,shugaoye/libvirt,nertpinx/libvirt,datto/libvirt,eskultety/libvirt,zhlcindy/libvirt-1.1.4-maintain,siboulet/libvirt-openvz,datto/libvirt,elmarco/libvirt,olafhering/libvirt,elmarco/libvirt,iam-TJ/libvirt,datto/libvirt,jfehlig/libvirt,eskultety/libvirt,rlaager/libvirt,libvirt/libvirt,jardasgit/libvirt,andreabolognani/libvirt,rlaager/libvirt,VenkatDatta/libvirt,siboulet/libvirt-openvz,cbosdo/libvirt,trainstack/libvirt,olafhering/libvirt,agx/libvirt,jardasgit/libvirt,shugaoye/libvirt,taget/libvirt,taget/libvirt,zhlcindy/libvirt-1.1.4-maintain,crobinso/libvirt,nertpinx/libvirt,iam-TJ/libvirt,trainstack/libvirt,crobinso/libvirt,VenkatDatta/libvirt,eskultety/libvirt,rlaager/libvirt,libvirt/libvirt,crobinso/libvirt,cbosdo/libvirt,fabianfreyer/libvirt,taget/libvirt,agx/libvirt,taget/libvirt,datto/libvirt,fabianfreyer/libvirt,libvirt/libvirt,zhlcindy/libvirt-1.1.4-maintain,iam-TJ/libvirt,iam-TJ/libvirt,zhlcindy/libvirt-1.1.4-maintain,VenkatDatta/libvirt,VenkatDatta/libvirt,shugaoye/libvirt,jardasgit/libvirt,eskultety/libvirt,jfehlig/libvirt,andreabolognani/libvirt,iam-TJ/libvirt,jfehlig/libvirt,trainstack/libvirt,eskultety/libvirt,siboulet/libvirt-openvz,nertpinx/libvirt,zippy2/libvirt,jardasgit/libvirt,iam-TJ/libvirt,zippy2/libvirt,jfehlig/libvirt,andreabolognani/libvirt,cbosdo/libvirt,fabianfreyer/libvirt,elmarco/libvirt,crobinso/libvirt,cbosdo/libvirt,elmarco/libvirt,datto/libvirt,elmarco/libvirt,VenkatDatta/libvirt,taget/libvirt,trainstack/libvirt,iam-TJ/libvirt,trainstack/libvirt,fabianfreyer/libvirt,rlaager/libvirt,agx/libvirt,agx/libvirt,zhlcindy/libvirt-1.1.4-maintain,shugaoye/libvirt,shugaoye/libvirt,olafhering/libvirt,jardasgit/libvirt,olafhering/libvirt,zippy2/libvirt,zippy2/libvirt,cbosdo/libvirt,siboulet/libvirt-openvz,rlaager/libvirt,trainstack/libvirt,nertpinx/libvirt,libvirt/libvirt