ext4: Fix compilation warning with gcc 4.5.2

Fixes uninitialized variable warning.

Change-Id: I537b02a1f78c122de974daf0b4e9b7344f10d3b6
Acked-by: Kaushik Sikdar <ksikdar@qti.qualcomm.com>
Signed-off-by: Rohit Vaswani <rvaswani@codeaurora.org>
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index abcdeab..9a66ff9 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -2088,7 +2088,7 @@
 ext4_ext_in_cache(struct inode *inode, ext4_lblk_t block,
 			struct ext4_extent *ex)
 {
-	struct ext4_ext_cache cex;
+	struct ext4_ext_cache cex = {0, 0, 0};
 	int ret = 0;
 
 	if (ext4_ext_check_cache(inode, block, &cex)) {