Avoid partial initialization warning.

Clang compiler is picky about partial initialization and
here we only need to initialize the 'len' field.

BUG: 17410010
Change-Id: I718582cef96d5f4076b5ff1c7b8162327e7809b6
diff --git a/fs_mgr/fs_mgr_verity.c b/fs_mgr/fs_mgr_verity.c
index c9a2a9b..1d2e43f 100644
--- a/fs_mgr/fs_mgr_verity.c
+++ b/fs_mgr/fs_mgr_verity.c
@@ -120,7 +120,9 @@
 {
     int data_device;
     struct ext4_super_block sb;
-    struct fs_info info = {0};
+    struct fs_info info;
+
+    info.len = 0;  /* Only len is set to 0 to ask the device for real size. */
 
     data_device = open(blk_device, O_RDONLY);
     if (data_device < 0) {