convert hyper_socketpair() to pipe2

Signed-off-by: Lai Jiangshan <jiangshanlai@gmail.com>

src/init.c

@@ -424,7 +424,7 @@ static int hyper_setup_container(struct hyper_pod *pod)
 	void *stack;
 	int ret = -1;
 
-	if (hyper_socketpair(PF_UNIX, SOCK_STREAM, 0, arg.ctl_pipe) < 0) {
+	if (pipe2(arg.ctl_pipe, O_CLOEXEC) < 0) {
 		perror("create pipe between hyper init and pod init failed");
 		goto out;
 	}

src/util.c

@@ -430,21 +430,6 @@ int hyper_setfd_nonblock(int fd)
 	return flags;
 }
 
-int hyper_socketpair(int domain, int type, int protocol, int sv[2])
-{
-	if (socketpair(domain, type, protocol, sv) < 0) {
-		perror("socketpair failed");
-		return -1;
-	}
-
-	if (hyper_setfd_cloexec(sv[0]) < 0 ||
-	    hyper_setfd_cloexec(sv[1]) < 0) {
-		return -1;
-	}
-
-	return 0;
-}
-
 static void hyper_unmount_all(void)
 {
 	FILE *mtab;