No bug: [mozharness] Remove some no-op code that just calls a method from a parent...

No bug: [mozharness] Remove some no-op code that just calls a method from a parent class; r=me

This addresses the review comment from https://phabricator.services.mozilla.com/D6171

--HG--
extra : rebase_source : c28337e129d59bdf242c626111c0daa05ba9a27d
extra : absorb_source : fcde924e19bfa881ee93090d96e1db488116caf4
extra : source : a3f256bb12a265a3faaec636e2860ccb5cc286b4
extra : histedit_source : 60a284992f2066c8a00fa89cd982982911d1ad7c