AI 147028: Fix up aapt so it runs cleanly under the valgrind leak checker.

Automated import of CL 147028
diff --git a/tools/aapt/XMLNode.cpp b/tools/aapt/XMLNode.cpp
index d476567..50a2185 100644
--- a/tools/aapt/XMLNode.cpp
+++ b/tools/aapt/XMLNode.cpp
@@ -486,6 +486,7 @@
 XMLNode::XMLNode(const String8& filename)
     : mFilename(filename)
 {
+    memset(&mCharsValue, 0, sizeof(mCharsValue));
 }
 
 XMLNode::type XMLNode::getType() const