Libion: Remove unused variables

For build-system CFLAGS clean-up, fix unused variables.

Fix missing close of file descriptors. Explicitly exit after a fork.

Change-Id: I76affbc8647c3a760ed3cacc7f3ada3f59e283b1
diff --git a/libion/ion_test.c b/libion/ion_test.c
index 8872282..b7d5583 100644
--- a/libion/ion_test.c
+++ b/libion/ion_test.c
@@ -164,8 +164,9 @@
         printf("master->master? [%10s]\n", ptr);
         if (recvmsg(sd[0], &msg, 0) < 0)
             perror("master recv 1");
+        close(fd);
+        _exit(0);
     } else {
-        struct msghdr msg;
         struct cmsghdr *cmsg;
         char* ptr;
         int fd, recv_fd;
@@ -205,6 +206,7 @@
         strcpy(ptr, "child");
         printf("child sending msg 2\n");
         sendmsg(sd[1], &child_msg, 0);
+        close(fd);
     }
 }