This resolves the following error messages when building gtk+
documentation:
mv: cannot stat `gtk-faq': No such file or directory
mv: cannot stat `gtk-tut': No such file or directory
Fixes [BUGID #730]
Also adds docbook-utils-native to DEPENDS so we don't rely on
host documentation building tools.
Signed-off-by: Scott Garman <scott.a.garman@intel.com>