xfree86: Don't swallow ±iglx command line flag

We want to notice that it's set, but still pass it through to dix.
Return 0 to indicate this.

Signed-off-by: Adam Jackson <ajax@redhat.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>

hw/xfree86/common/xf86Init.c

@@ -1378,7 +1378,7 @@ ddxProcessArgument(int argc, char **argv, int i)
     }
     if (!strcmp(argv[i], "-iglx") || !strcmp(argv[i], "+iglx")) {
         xf86Info.iglxFrom = X_CMDLINE;
-        return 1;
+        return 0;
     }
 
     /* OS-specific processing */