Build status sanitizing

[ronanrodrigo]

We saw some Clean succeeded at our logs as build status. And checking on ParserBuildSteps it just extract extra terms when it contains "Build ".

public func parse(activityLog: IDEActivityLog) throws -> BuildStep {
    // ...
    buildStatus = activityLog.mainSection.localizedResultString.replacingOccurrences(of: "Build ", with: "")
    // ...
    return mainBuildStep
}