Fix error message to match CTS

Bug: 8657725
Change-Id: Ib608eb55f14d557d667f93e4f646c03d5ea470c1
diff --git a/services/medialog/MediaLogService.cpp b/services/medialog/MediaLogService.cpp
index f60749d..683fdf3 100644
--- a/services/medialog/MediaLogService.cpp
+++ b/services/medialog/MediaLogService.cpp
@@ -60,7 +60,9 @@
     static const String16 sDump("android.permission.DUMP");
     if (!(IPCThreadState::self()->getCallingUid() == AID_MEDIA ||
             PermissionCache::checkCallingPermission(sDump))) {
-        fdprintf(fd, "Permission denied.\n");
+        fdprintf(fd, "Permission Denial: can't dump media.log from pid=%d, uid=%d\n",
+                IPCThreadState::self()->getCallingPid(),
+                IPCThreadState::self()->getCallingUid());
         return NO_ERROR;
     }