always qemu_cpu_kick after unhalting a cpu

This ensures env->halt_cond is broadcast, and the loop in
qemu_tcg_wait_io_event and qemu_kvm_wait_io_event is exited
naturally rather than through a timeout.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
