imlib2_grab, imlib2_view: Unset context colormap

Should normally not be set when grabbing.

src/bin/imlib2_grab.c

@@ -92,6 +92,7 @@ main(int argc, char **argv)
    file = argv[0];
 
    prog_x11_init();
+   imlib_context_set_colormap(None);
 
    if (draw == None)
       draw = DefaultRootWindow(disp);

src/bin/imlib2_view.c

@@ -658,6 +658,7 @@ main(int argc, char **argv)
      }
 
    prog_x11_init();
+   imlib_context_set_colormap(None);
 
    win = prog_x11_create_window("imlib2_view", 10, 10);