dev-util/buildbot-worker: Fix conf.d and init.d filenames

dev-util/buildbot-worker: Fix conf.d and init.d filenames

The last two releases mistakenly installed the conf.d and init.d files using the old buildslave
name.  The 9999 ebuild had not been properly updated to the new buildbot_worker name.
As a result the 0.9.2 and 0.9.3 releases were installing them as buildslave.
This caused problems in downstream installations/scripts expecting the init script to be
named "buildbot_worker".

Package-Manager: Portage-2.3.3_p23, Repoman-2.3.1_p16