Merge a libxml clang warning fix

This fixes the following warning:

/usr/local/google/work/chrome/src/third_party/libxml/src/xpath.c:12269:13: warning: comparison of constant 18 with expression of type 'xmlXPathTypeVal' is always false [-Wtautological-constant-out-of-range-compare]
                        if (type == XML_NAMESPACE_DECL)
                            ~~~~ ^  ~~~~~~~~~~~~~~~~~~

The upstream fix is at http://git.gnome.org/browse/libxml2/commit/?id=713434d2309da469d64b35e163ea6556dadccada

TEST=none
BUG=151927

Review URL: https://codereview.chromium.org/10984039

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@158800 0039d316-1c4b-4281-b951-d872f2087c98
2 files changed