chore(scripts): Fix OpenShift detection in setup-vcluster-env.sh

[jopit]

The test to detect OpenShift in the setup-vcluster-env.sh script

	if kubectl api-resources | grep -q "openshift.io"; then
		OPENSHIFT=true
	fi

is not working. grep -q will return success as soon as it detects the first match. This will close the pipe between the kubectl command and the grep command. The kubectl command will then try to write its next result to the closed pipe, causing it to error out. Since the script has set set -o pipefail, the entire pipeline will then error out, resulting in the OPENSHIFT variable not being set.

This PR fixes this by forcing the kubectl step to always exit successfully.

[jannfis]

Good catch! I wasn't aware of kubectl's behaviour in this regard.

LGTM.