VerifyPodLabels had no callers anywhere in the repo, and it was the only
caller of VerifyAppLabels, which in turn was the only caller of the
checkLabel and combineErrors helpers. Remove the whole dead cluster (and
the now-unused strings, github.com/pkg/errors, and ceph/controller
imports). AssertLabelsContainCephRequirements in the same file remains and
is unaffected. Verified with grep, deadcode, and staticcheck.
Signed-off-by: Joshua Hoblitt <josh@hoblitt.com>
(cherry picked from commit ac75488621)