Update to libxml2 2.9.4 by merging commit 'd8083bf7' into klp-dev. am: 312a2fc2f0 am: 7e8d493a9a am: 688b79dd3b  -s ours am: dcf08c71f8
am: 4c1605a631

Change-Id: If1ec915414a8167ee0e789313d84100ab20c2c68