10125 smatch fixes for cmd-inet

@@ -6,10 +6,15 @@
  *  This program is free software; you can redistribute it and/or
  *  modify it under the terms of the GNU General Public License
  *  as published by the Free Software Foundation; either version
  *  2 of the License, or (at your option) any later version.
  */
+
+/*
+ * Copyright (c) 2018, Joyent, Inc.
+ */
+
 #include <errno.h>
 #include <unistd.h>
 #include <fcntl.h>
 #include <sys/wait.h>
 #include <syslog.h>

@@ -68,11 +73,11 @@
         (void) seteuid(getuid());
         (void) setegid(getgid());
         argv[0] = promptprog;
         argv[1] = user == NULL ? "" : user;
         argv[2] = remote_name;
-        slprintf(fdstr, sizeof (fdstr), "%d", p[1]);
+        (void) slprintf(fdstr, sizeof (fdstr), "%d", p[1]);
         argv[3] = fdstr;
         argv[4] = NULL;
         (void) execv(*argv, argv);
         _exit(127);
     }