Drop the vm_running global variable

Use runstate_is_running() instead, which is introduced by this commit.

Signed-off-by: Luiz Capitulino <[email protected]>
diff --git a/xen-all.c b/xen-all.c
index b119817..b5e28ab 100644
--- a/xen-all.c
+++ b/xen-all.c
@@ -736,7 +736,7 @@
          * guest resumes and does a hlt with interrupts disabled which
          * causes Xen to powerdown the domain.
          */
-        if (vm_running) {
+        if (runstate_is_running()) {
             if (qemu_shutdown_requested_get()) {
                 destroy_hvm_domain();
             }