Add a comment to indicate what this file is for.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@38533 91177308-0d34-0410-b5e6-96231b3b80d8

ModuleInfo.txt

@@ -1,3 +1,4 @@
+# This file provides information for llvm-top
 DepModule: llvm 
 ConfigCmd:
 ConfigTest: