Fix method name in RetryBuildService

What does this MR do and why?

• Rename reprocess! method to clone! since it's about cloning a build. The reprocessing part occurs outside this method. I found this method name confusing since it's also used in RetryPipelineService with the purpose of only cloning the builds and then issue a reprocessing of the whole pipeline at the end.
• Remove needs variable since it's not used anymore. It was added here and removed here but we didn't remove the variable.

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