admin: reject clients unless their UID matches the current UID
admin: reject clients unless their UID matches the current UID

The admin protocol RPC messages are only intended for use by the user
running the daemon. As such they should not be allowed for any client
UID that does not match the server UID.

Fixes CVE-2019-10132

Reviewed-by: Ján Tomko <4cab11cfb98d3c937327354a78eb07dbb6ee2bc6@redhat.com>
Signed-off-by: Daniel P. Berrangé <bb938cf255e055ff3507f2627d214e8e62118fcf@redhat.com>

jfehlig/libvirt,nertpinx/libvirt,libvirt/libvirt,fabianfreyer/libvirt,crobinso/libvirt,jardasgit/libvirt,crobinso/libvirt,libvirt/libvirt,libvirt/libvirt,zippy2/libvirt,andreabolognani/libvirt,crobinso/libvirt,jardasgit/libvirt,libvirt/libvirt,fabianfreyer/libvirt,jfehlig/libvirt,eskultety/libvirt,eskultety/libvirt,andreabolognani/libvirt,zippy2/libvirt,eskultety/libvirt,fabianfreyer/libvirt,nertpinx/libvirt,andreabolognani/libvirt,jardasgit/libvirt,jardasgit/libvirt,eskultety/libvirt,andreabolognani/libvirt,jfehlig/libvirt,fabianfreyer/libvirt,jfehlig/libvirt,olafhering/libvirt,zippy2/libvirt,eskultety/libvirt,olafhering/libvirt,olafhering/libvirt,nertpinx/libvirt,fabianfreyer/libvirt,olafhering/libvirt,zippy2/libvirt,nertpinx/libvirt,jardasgit/libvirt,nertpinx/libvirt,andreabolognani/libvirt,crobinso/libvirt