SwiftLint2

Rename label of tuple

It fixes following error:
> Source/swiftlint/Commands/LintCommand.swift:35:27: error: cannot invoke 'appendContentsOf' with an argument list of type '([(rule: String, time: Double)])'
>                ruleTimes.appendContentsOf(currentRuleTimes)
>                          ^
>Source/swiftlint/Commands/LintCommand.swift:35:27: note: expected an argument list of type '(C)'
>                ruleTimes.appendContentsOf(currentRuleTimes)
>                          ^

It seems Swift does not allow label mismatch on that.