fix broken migration

While fixing migration with -S, commit
89befdd1a6 broke the rest of us. Poor
glommer, with a poor family, spare him his life from this monstruosity.

Since the unconditional vm_start, not autostart was the villain, I'm putting
back autostart. Let me know if you prefer other solutions, it doesn't really matter,
doesn't really matter to me.

Any way the wind blows...

Signed-off-by: Glauber Costa <glommer@redhat.com>
CC: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Glauber Costa <glommer@redhat.com>

vl.c

@@ -5721,8 +5721,10 @@ int main(int argc, char **argv, char **envp)
     if (loadvm)
         do_loadvm(loadvm);
 
-    if (incoming)
+    if (incoming) {
+        autostart = 0;
         qemu_start_incoming_migration(incoming);
+    }
 
     if (autostart)
         vm_start();