move qemu-kvm.upstart to qemu-system-x86 package

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
 Support upgrade from qemu-kvm on non-x86 arches:

    - Add Provides: qemu-kvm, kvm to qemu-system-{arm,ppc,sparc,x86}
    - Add Breaks/Replaces for qemu-{common,system,kvm} and kvm.

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>