Add libxml2 to userspace manifest

Change-Id: I7ae92b23c350b93c8b88c5f13cb1f7860d55c685
diff --git a/userspace b/userspace
index 1aa2d19..15e13dd 100644
--- a/userspace
+++ b/userspace
@@ -343,6 +343,11 @@
              remote="https://fuchsia.googlesource.com/third_party/libvpx"
              gerrithost="https://fuchsia-review.googlesource.com"
              githooks="manifest/git-hooks"/>
+    <project name="third_party/libxml2"
+             path="third_party/libxml2"
+             remote="https://fuchsia.googlesource.com/third_party/libxml2"
+             gerrithost="https://fuchsia-review.googlesource.com"
+             githooks="manifest/git-hooks"/>
     <project name="third_party/lua"
              path="third_party/lua"
              remote="https://fuchsia.googlesource.com/third_party/lua"