Fix: xml: Do not prune meaningful leaves from v1 patchsets

Otherwise, we could lose things being added like:
<resource_set id="rsc-set-1">
  <resource_ref id="rsc1"/>
  <resource_ref id="rsc2"/>
</resource_set>
Merge pull request #508 from gao-yan/xml-patchset-v1-fixes

Fixes for xml v1 patchsets