Fix for a memory leak in the stream cache

[Sergio Villar Senin <svillar igalia com>]

A hash table that was not freed in finalize

Br

Index: libtinymail/tny-fs-stream-cache.c
===================================================================
--- libtinymail/tny-fs-stream-cache.c	(revision 3738)
+++ libtinymail/tny-fs-stream-cache.c	(working copy)
@@ -337,6 +337,9 @@
 	TnyFsStreamCache *self = (TnyFsStreamCache *)object;
 	TnyFsStreamCachePriv *priv = TNY_FS_STREAM_CACHE_GET_PRIVATE (self);
 
+	if (priv->cached_files)
+		g_hash_table_unref (priv->cached_files);
+
 	if (priv->path) {
 		g_free (priv->path);
 		priv->path = NULL;