Fix info leak vulnerability of IDrm

bug: 26323455
Change-Id: I25bb30d3666ab38d5150496375ed2f55ecb23ba8
diff --git a/media/libmedia/IDrm.cpp b/media/libmedia/IDrm.cpp
index b1ad0c5..7c709cd 100644
--- a/media/libmedia/IDrm.cpp
+++ b/media/libmedia/IDrm.cpp
@@ -658,7 +658,7 @@
 
             Vector<uint8_t> request;
             String8 defaultUrl;
-            DrmPlugin::KeyRequestType keyRequestType;
+            DrmPlugin::KeyRequestType keyRequestType = DrmPlugin::kKeyRequestType_Unknown;
 
             status_t result = getKeyRequest(sessionId, initData, mimeType,
                     keyType, optionalParameters, request, defaultUrl,