selftests/bpf: Handle SIGINT when creating netns

It's necessary to delete netns during the MPTCP bpf tests interrupt,
otherwise the next tests run will fail due to unable to create netns.

This patch adds a new SIGINT handle sig_int, and deletes NS_TEST in it.

Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
Reviewed-by: Mat Martineau <martineau@kernel.org>

tools/testing/selftests/bpf/network_helpers.c

@@ -693,6 +693,12 @@ void del_netns(struct nstoken *token, const char *name)
 		log_err("del netns %s failed", name);
 }
 
+static void sig_int(int sig)
+{
+	signal(sig, SIG_IGN);
+//	del_netns(token, name);
+}
+
 struct nstoken *add_netns(const char *name)
 {
 	if (SYS_NOFAIL("ip netns add %s", name)) {
@@ -706,5 +712,6 @@ struct nstoken *add_netns(const char *name)
 		return NULL;
 	}
 
+	signal(SIGINT, sig_int);
 	return open_netns(name);
 }