qrexec: fix arguments handling

Don't parse options for local command as qrexec-client-vm's own options.

Fixes QubesOS/qubes-issues#3762

qrexec/qrexec-client-vm.c

@@ -113,7 +113,7 @@ int main(int argc, char **argv)
     int opt;
 
     while (1) {
-        opt = getopt_long(argc, argv, "", longopts, NULL);
+        opt = getopt_long(argc, argv, "+", longopts, NULL);
         if (opt == -1)
             break;
         switch (opt) {