[Gateway] Geneve interface cleanup

[cheina97]

Description

This PR fixes the geneve interfaces cleanup in liqo gateway

[adamjensenbot]

Hi @cheina97. Thanks for your PR!

I am @adamjensenbot.
You can interact with me issuing a slash command in the first line of a comment.
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  when the rebase operation is completed)
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Make sure this PR appears in the liqo changelog, adding one of the following labels:

• feat: 🚀 New Feature
• fix: 🐛 Bug Fix
• refactor: 🧹 Code Refactoring
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[cheina97]

/rebase test=true