virsh: Unregister the connection close notifier upon termination
virsh: Unregister the connection close notifier upon termination

Before closing the connection we unregister the close callback
to prevent a reference leak.

Further, the messages on virConnectClose != 0 are a bit more specific
now.

Signed-off-by: Viktor Mihajlovski <a96a137ca8976b5ff3114c85be7aeb3b6464dad7@linux.vnet.ibm.com>

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