Clean up internal usage of g*Converter for manifest/matrix.

Change to toXml / fromXml instead.

Test: pass
Change-Id: I9326c6ea5003800108f4f9d6ac831ba815c21f0b
diff --git a/CompatibilityMatrix.cpp b/CompatibilityMatrix.cpp
index 8ca2dbd..6fc6675 100644
--- a/CompatibilityMatrix.cpp
+++ b/CompatibilityMatrix.cpp
@@ -120,8 +120,7 @@
 
 status_t CompatibilityMatrix::fetchAllInformation(const FileSystem* fileSystem,
                                                   const std::string& path, std::string* error) {
-    return details::fetchAllInformation(fileSystem, path, gCompatibilityMatrixConverter, this,
-                                        error);
+    return details::fetchAllInformation(fileSystem, path, this, error);
 }
 
 std::string CompatibilityMatrix::getXmlSchemaPath(const std::string& xmlFileName,