patch 8.2.1715: Motif GUI: commented out code missed {}

Problem:    Motif GUI: commented out code missed {}.
Solution:   Add {} and reenable the code. (similar to #6989)
diff --git a/src/gui_motif.c b/src/gui_motif.c
index 57d50b0..543304f 100644
--- a/src/gui_motif.c
+++ b/src/gui_motif.c
@@ -1242,11 +1242,11 @@
     }
     else
     {
-# if 0  // DISABLED - this causes a crash when running "make test_gui" in
 	// Test_colorscheme()
 	if (menu->xpm_fname != NULL)
+	{
 	    XtSetArg(args[n], XmNpixmapFile, menu->xpm_fname); n++;
-# endif
+	}
 	XtSetArg(args[n], XmNpixmapData, menu->xpm); n++;
 	XtSetArg(args[n], XmNlabelLocation, XmBOTTOM); n++;
     }