Avoid pointlessly setting argv[0]

It will just be overwritten later.  No functional change intended.

libqrexec/exec.c

@@ -52,27 +52,28 @@ void exec_qubes_rpc_if_requested(const char *prog, char *const envp[]) {
         char *prog_copy;
         char *tok, *savetok;
         char *argv[16]; // right now 6 are used, but allow future extensions
-        size_t i = 0;
+        size_t i = 1;
 
         if (prog[RPC_REQUEST_COMMAND_LEN] != ' ') {
             LOG(ERROR, "\"" RPC_REQUEST_COMMAND "\" not followed by space");
             _exit(126);
         }
 
-        prog_copy = strdup(prog);
+        prog_copy = strdup(prog + RPC_REQUEST_COMMAND_LEN + 1);
         if (!prog_copy) {
             PERROR("strdup");
             _exit(QREXEC_EXIT_PROBLEM);
         }
 
         tok=strtok_r(prog_copy, " ", &savetok);
-        do {
+        while (tok != NULL) {
             if (i >= sizeof(argv)/sizeof(argv[0])-1) {
                 LOG(ERROR, "To many arguments to %s", RPC_REQUEST_COMMAND);
                 _exit(QREXEC_EXIT_PROBLEM);
             }
             argv[i++] = tok;
-        } while ((tok=strtok_r(NULL, " ", &savetok)));
+            tok=strtok_r(NULL, " ", &savetok);
+        }
         argv[i] = NULL;
 
         argv[0] = getenv("QREXEC_MULTIPLEXER_PATH");