Tweak the module map file test slightly, by putting one of the headers

into a submodule. Submodules aren't actually supported anywhere else,
but we do parse them, so this verifies that we're at least seeing
through them properly.

llvm-svn: 144436

clang/test/Modules/Inputs/normal-module-map/module.map

@@ -1,5 +1,5 @@
 module libA {
-  header "a1.h"
+  module a1 { header "a1.h" }
   header "a2.h"
 }