Fix header guards in libjingle_xmpp/xmllite.

Bug: 919085
Change-Id: I9b2a1375d8e3023b561bbaff94c8024c93537033
Reviewed-on: https://chromium-review.googlesource.com/c/1397602
Reviewed-by: Harald Alvestrand <hta@chromium.org>
Commit-Queue: Mirko Bonadei <mbonadei@chromium.org>
Cr-Commit-Position: refs/heads/master@{#620286}
7 files changed