virt: cpuflags kill VM when disk image is unbootable.

Signed-off-by: NJiří Župka <jzupka@redhat.com>

qemu/tests/cpuflags.py

@@ -81,11 +81,16 @@ def run_cpuflags(test, params, env):
             vm.create(migration_mode=mig_protocol)
         else:
             vm.create()
-        vm.verify_alive()
 
         session = None
+        try:
+            vm.verify_alive()
+
             if wait:
                 session = vm.wait_for_login()
+        except qemu_vm.ImageUnbootableError:
+            vm.destroy(gracefully=False)
+            raise
 
         return (vm, session)