fix ISE in cluster version detection

[simkam]

fixes #519

supersedes #541

Please make sure your PR meets the following requirements:

• [x] Pull Request contains a description of the changes
• [x] Pull Request does not include fixes for multiple issues/topics
• [x] Code is formatted, imports ordered, code compiles and tests are passing
• [x] Code is self-descriptive and/or documented

[mnovak1]

@simkam Can we have any CI runs like in https://github.com/xtf-cz/xtf/pull/541#issuecomment-1582416570 ?

[simkam]

• detected from cluster - 4.13.3 -- eap-8.x-openshift-4-80-openjdk17/247/ :heavy_check_mark:

  [2023-06-28 11:11:17,534] DEBUG- Trying to determine OpenShift client url for cluster version 4.13.3.
  [2023-06-28 11:11:17,612] DEBUG- Trying to load OpenShift client archive from cache (enabled: true) or download it from https://mirror.openshift.com/pub/openshift-v4/amd64/clients/ocp/4.13.3/openshift-client-linux.tar.gz.
  [2023-06-28 11:11:17,615] DEBUG- OpenShift client archive not found in cache, downloading it.

• detected from cluster - 4.14.0-ec.1 -- eap-8.x-openshift-4-80-openjdk17/248/ :heavy_check_mark:

  [2023-06-28 11:11:51,524] DEBUG- Trying to determine OpenShift client url for cluster version 4.14.0-ec.1.
  [2023-06-28 11:11:51,595] DEBUG- Trying to load OpenShift client archive from cache (enabled: true) or download it from https://mirror.openshift.com/pub/openshift-v4/amd64/clients/ocp-dev-preview/4.14.0-ec.1/openshift-client-linux.tar.gz.
  [2023-06-28 11:11:51,599] DEBUG- OpenShift client archive not found in cache, downloading it.

• manually added by -Dxtf.openshift.version=4.9.0-rc.3 - client not available at mirror.openshift.com - default to configured channel -- eap-8.x-openshift-4-80-openjdk17/249/ :heavy_check_mark:

  [2023-06-28 11:12:16,093] DEBUG- Trying to determine OpenShift client url for cluster version 4.9.0-rc.3.
  [2023-06-28 11:12:16,647] DEBUG- Trying to load OpenShift client archive from cache (enabled: true) or download it from https://mirror.openshift.com/pub/openshift-v4/amd64/clients/ocp/stable/openshift-client-linux.tar.gz.
  [2023-06-28 11:12:16,652] DEBUG- OpenShift client archive not found in cache, downloading it. 

• manually added by -Dxtf.openshift.version=4.9.0-rc.7 - client available -- eap-8.x-openshift-4-80-openjdk17/250/ :heavy_check_mark:

  [2023-06-28 11:29:35,155] DEBUG- Trying to determine OpenShift client url for cluster version 4.9.0-rc.7.
  [2023-06-28 11:29:35,672] DEBUG- Trying to load OpenShift client archive from cache (enabled: true) or download it from https://mirror.openshift.com/pub/openshift-v4/amd64/clients/ocp/4.9.0-rc.7/openshift-client-linux.tar.gz.
  [2023-06-28 11:29:35,675] DEBUG- OpenShift client archive not found in cache, downloading it.
  

[mnovak1]

@simkam thanks, merging.