Set nova config allow_resize_on_same_host

Include --allow_resize_on_same_host in nova.conf to allow the
tempest resize tests to proceed against devstack.

Change-Id: Ifd030ed591d63146c21e640240398a81cee194cd
diff --git a/stack.sh b/stack.sh
index 6bbf302..34936d4 100755
--- a/stack.sh
+++ b/stack.sh
@@ -1189,6 +1189,7 @@
 rm -f $NOVA_CONF/nova.conf
 add_nova_flag "--verbose"
 add_nova_flag "--allow_admin_api"
+add_nova_flag "--allow_resize_to_same_host"
 add_nova_flag "--scheduler_driver=$SCHEDULER"
 add_nova_flag "--dhcpbridge_flagfile=$NOVA_CONF/nova.conf"
 add_nova_flag "--fixed_range=$FIXED_RANGE"