Fix violations introduced when linting with Swift 4.1

[marcelofabri]

Part of #2021

Not adding a changelog entry because it doesn't impact users.

[SwiftLintBot]

	1 Warning
⚠️	Please include a CHANGELOG entry to credit yourself! You can find it at CHANGELOG.md.

	12 Messages
📖	Linting Aerial with this PR took 0.47s vs 0.41s on master (14% slower)
📖	Linting Alamofire with this PR took 3.48s vs 3.45s on master (0% slower)
📖	Linting Firefox with this PR took 13.67s vs 13.5s on master (1% slower)
📖	Linting Kickstarter with this PR took 21.12s vs 21.05s on master (0% slower)
📖	Linting Moya with this PR took 1.87s vs 1.82s on master (2% slower)
📖	Linting Nimble with this PR took 2.0s vs 1.95s on master (2% slower)
📖	Linting Quick with this PR took 0.58s vs 0.56s on master (3% slower)
📖	Linting Realm with this PR took 3.63s vs 3.55s on master (2% slower)
📖	Linting SourceKitten with this PR took 1.14s vs 1.13s on master (0% slower)
📖	Linting Sourcery with this PR took 5.1s vs 4.87s on master (4% slower)
📖	Linting Swift with this PR took 14.54s vs 13.95s on master (4% slower)
📖	Linting WordPress with this PR took 15.49s vs 15.16s on master (2% slower)

Here's an example of your CHANGELOG entry:

* Fix violations introduced when linting with Swift 4.1.  
  [marcelofabri](https://github.com/marcelofabri)
  [#issue_number](https://github.com/realm/SwiftLint/issues/issue_number)

note: There are two invisible spaces after the entry's text.

Generated by 🚫 Danger

[codecov-io]

Codecov Report

Merging #2037 into master will increase coverage by 0.01%.
The diff coverage is 80%.

@@            Coverage Diff             @@
##           master    #2037      +/-   ##
==========================================
+ Coverage   89.64%   89.66%   +0.01%     
==========================================
  Files         256      256              
  Lines       14886    14887       +1     
  Branches      969      969              
==========================================
+ Hits        13345    13348       +3     
+ Misses       1523     1521       -2     
  Partials       18       18

Impacted Files	Coverage Δ
...FrameworkTests/CyclomaticComplexityRuleTests.swift	100% <ø> (ø)	⬆️
...SwiftLintFramework/Extensions/File+SwiftLint.swift	94.73% <ø> (-0.02%)	⬇️
Source/swiftlint/Commands/LintCommand.swift	0% <0%> (ø)	⬆️
Source/SwiftLintFramework/Models/YamlParser.swift	87.27% <100%> (ø)	⬆️
Source/SwiftLintFramework/Models/Location.swift	90% <100%> (ø)	⬆️
...s/SwiftLintFrameworkTests/ConfigurationTests.swift	93.66% <100%> (+0.05%)	⬆️
.../SwiftLintFrameworkTests/Yaml+SwiftLintTests.swift	89.18% <100%> (ø)	⬆️
...LintFramework/Rules/CyclomaticComplexityRule.swift	90.16% <50%> (-0.16%)	⬇️
...iftLintFramework/Extensions/String+SwiftLint.swift	70.66% <66.66%> (+1.22%)	⬆️
Source/SwiftLintFramework/Models/Command.swift	97.77% <0%> (+2.12%)	⬆️

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