patch 7.4.1552
Problem:    ":colorscheme" does not use 'packpath'.
Solution:   Also use in "start" and "opt" directories in 'packpath'.
diff --git a/src/eval.c b/src/eval.c
index 765d9b9..0b589fd 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -23942,7 +23942,7 @@
 	}
 
 	/* Try loading the package from $VIMRUNTIME/autoload/<name>.vim */
-	if (source_runtime(scriptname, FALSE) == OK)
+	if (source_runtime(scriptname, 0) == OK)
 	    ret = TRUE;
     }