Fix a couple of mistakes in get_ipam_cidr calls

(first one only caused a slight slow-down; second one only mattered if
your 'weave' container had a non-standard name)

weave

@@ -915,7 +915,7 @@ case "$COMMAND" in
         shift $CIDR_COUNT
         CONTAINER=$(docker run $DNS_ARGS -d "$@")
         create_bridge
-        get_ipam_cidr $CONTAINER_ID $CONTAINER
+        get_ipam_cidr $CONTAINER $CONTAINER
         with_container_netns $CONTAINER attach $CIDR_ARGS >/dev/null
         tell_dns PUT $CONTAINER $CIDR_ARGS
         echo $CONTAINER
@@ -981,7 +981,7 @@ case "$COMMAND" in
     expose)
         collect_cidr_args "$@"
         shift $CIDR_COUNT
-        get_ipam_cidr weave weave:expose
+        get_ipam_cidr $CONTAINER_NAME weave:expose
         if [ $# -eq 0 ]; then
             FQDN=""
         else