Skip cache removal when file does not exist

[chrismuellner]

Description

Install agent binaries when installed version is "" (empty), but the <tenant>/bin/<target version> directory exists. This means the previous attempt to install agent failed (e.g. OOM during unzip), only created the bin folder but did not update the database with the correct version.

How can this be tested?

Dynakube that needs CSI driver is deployed:

1. CSI driver crashes during unzip (after creating bin folder with version)
2. CSI driver restarts and tries to update ruxitagentproc.conf without an installed version

Checklist

• Unit tests have been updated/added
• PR is labeled accordingly

[waodim]

apart from the points which @meik99 brought up, which are already resolved anyway, everything looks fine to me.

done