[libclang] Put the RecursiveASTVisitor in libclang in a cxindex namespace.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@156331 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/libclang/IndexBody.cpp b/tools/libclang/IndexBody.cpp
index e1b9f2a..9a829f8 100644
--- a/tools/libclang/IndexBody.cpp
+++ b/tools/libclang/IndexBody.cpp
@@ -16,7 +16,7 @@
 
 namespace {
 
-class BodyIndexer : public RecursiveASTVisitor<BodyIndexer> {
+class BodyIndexer : public cxindex::RecursiveASTVisitor<BodyIndexer> {
   IndexingContext &IndexCtx;
   const NamedDecl *Parent;
   const DeclContext *ParentDC;