Fix up SRU recordData with pseudo root
Fix up SRU recordData with pseudo root

This is to make recordData XML parseable (document) in case it is an
XML fragment. The inserted root is <yaz-record>. Fixes #4453.

nla/yaz,dcrossleyau/yaz,nla/yaz,dcrossleyau/yaz,dcrossleyau/yaz,nla/yaz,nla/yaz