ceph: zero unused message header, footer fields

We shouldn't leak any prior memory contents to other parties.  And random
data, particularly in the 'version' field, can cause problems down the
line.

Signed-off-by: Sage Weil <sage@newdream.net>
diff --git a/fs/ceph/messenger.c b/fs/ceph/messenger.c
index 509f57d..a3a8f36 100644
--- a/fs/ceph/messenger.c
+++ b/fs/ceph/messenger.c
@@ -2085,15 +2085,19 @@
 	kref_init(&m->kref);
 	INIT_LIST_HEAD(&m->list_head);
 
+	m->hdr.tid = 0;
 	m->hdr.type = cpu_to_le16(type);
+	m->hdr.priority = cpu_to_le16(CEPH_MSG_PRIO_DEFAULT);
+	m->hdr.version = 0;
 	m->hdr.front_len = cpu_to_le32(front_len);
 	m->hdr.middle_len = 0;
 	m->hdr.data_len = cpu_to_le32(page_len);
 	m->hdr.data_off = cpu_to_le16(page_off);
-	m->hdr.priority = cpu_to_le16(CEPH_MSG_PRIO_DEFAULT);
+	m->hdr.reserved = 0;
 	m->footer.front_crc = 0;
 	m->footer.middle_crc = 0;
 	m->footer.data_crc = 0;
+	m->footer.flags = 0;
 	m->front_max = front_len;
 	m->front_is_vmalloc = false;
 	m->more_to_follow = false;