Fix stack content leak vulnerability in mediaserver

bug: 30875060
Change-Id: I03f4d08b7b31ac5b507cfc9e65e5607c73972d95
(cherry picked from commit 9a6861cbd3bb0e1b8fe4c105795256ee032f9664)
diff --git a/media/libmedia/IDrm.cpp b/media/libmedia/IDrm.cpp
index 7c709cd..6f6530b 100644
--- a/media/libmedia/IDrm.cpp
+++ b/media/libmedia/IDrm.cpp
@@ -912,7 +912,7 @@
             readVector(data, keyId);
             readVector(data, message);
             readVector(data, signature);
-            bool match;
+            bool match = false;
             uint32_t result = verify(sessionId, keyId, message, signature, match);
             reply->writeInt32(match);
             reply->writeInt32(result);