Log Message:
-----------
Fix segfault when xpath_list function is applied to an invalid document.
John Gray
Modified Files:
--------------
pgsql/contrib/xml2:
xpath.c (r1.5 -> r1.6)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/xml2/xpath.c.diff?r1=1.5&r2=1.6)