selftests: mptcp: update userspace pm subflow tests

To align with what is done by the in-kernel PM, update userspace pm
subflow selftests, by sending the a remove_addrs command together
before the remove_subflows command. This will get a RM_ADDR in
chk_rm_nr().

Fixes: d9a4594 ("mptcp: netlink: Add MPTCP_PM_CMD_REMOVE")
Fixes: 5e986ec ("selftests: mptcp: userspace pm subflow tests")
Link: multipath-tcp/mptcp_net-next#379
Signed-off-by: Geliang Tang <geliang.tang@suse.com>

tools/testing/selftests/net/mptcp/mptcp_join.sh

@@ -941,6 +941,7 @@ do_transfer()
 				sleep 1
 				sp=$(grep "type:10" "$evts_ns2" |
 				     sed -n 's/.*\(sport:\)\([[:digit:]]*\).*$/\2/p;q')
+				ip netns exec ${connector_ns} ./pm_nl_ctl rem token $tk id $id
 				ip netns exec ${connector_ns} ./pm_nl_ctl dsf lip $addr lport $sp \
 									rip $da rport $dp token $tk
 			fi
@@ -3156,7 +3157,7 @@ userspace_tests()
 		pm_nl_set_limits $ns1 0 1
 		run_tests $ns1 $ns2 10.0.1.1 0 0 userspace_1 slow
 		chk_join_nr 1 1 1
-		chk_rm_nr 0 1
+		chk_rm_nr 1 1
 		kill_events_pids
 	fi
 }