Fix an assertion ted was hitting, due to an uninitialized variable.

llvm-svn: 49678
diff --git a/clang/lib/Rewrite/RewriteRope.cpp b/clang/lib/Rewrite/RewriteRope.cpp
index 9b092be..2b9ff55 100644
--- a/clang/lib/Rewrite/RewriteRope.cpp
+++ b/clang/lib/Rewrite/RewriteRope.cpp
@@ -53,7 +53,7 @@
     /// is an instance of RopePieceBTreeInterior.
     bool IsLeaf;
     
-    RopePieceBTreeNode(bool isLeaf) : IsLeaf(isLeaf) {}
+    RopePieceBTreeNode(bool isLeaf) : Size(0), IsLeaf(isLeaf) {}
     ~RopePieceBTreeNode() {}
   public: