xml: T5854: clear empty paths left by embedded override of defaultValue

[jestabro]

Change Summary

For overriding defaultValue elements with XML fragments containing parent nodes, one needs to clean up leftover empty paths: example use case:

#include <include/accel-ppp/radius-additions.xml.i>
 <node name="radius">
   <children>
     <leafNode name="timeout">
       <defaultValue>30</defaultValue>
     </leafNode>
     <leafNode name="acct-timeout">
       <defaultValue>30</defaultValue>
     </leafNode>
   </children>
 </node>

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Code style update (formatting, renaming)
• Refactoring (no functional changes)
• Migration from an old Vyatta component to vyos-1x, please link to related PR inside obsoleted component
• Other (please describe):

Related Task(s)

• https://vyos.dev/T5854

Related PR(s)

Component(s) name

Proposed changes

How to test

Smoketest result

Checklist:

• I have read the CONTRIBUTING document
• I have linked this PR to one or more Phabricator Task(s)
• I have run the components SMOKETESTS if applicable
• My commit headlines contain a valid Task id
• My change requires a change to the documentation
• I have updated the documentation accordingly

[c-po]

@Mergifyio backport sagitta

[mergify]

backport sagitta

✅ Backports have been created

• #2680 xml: T5854: clear empty paths left by embedded override of defaultValue (backport #2679) has been created for branch sagitta