"Comparison method violates its general contract!" fix LevenshteinComparator

Receiving the following IllegalArgumentException. Traced back to incomplete Levenshtein comparator.

```
Exception in thread "main" java.lang.IllegalArgumentException: Comparison method violates its general contract!
       at java.util.TimSort.mergeLo(TimSort.java:747)
       at java.util.TimSort.mergeAt(TimSort.java:483)
       at java.util.TimSort.mergeCollapse(TimSort.java:410)
       at java.util.TimSort.sort(TimSort.java:214)
       at java.util.TimSort.sort(TimSort.java:173)
       at java.util.Arrays.sort(Arrays.java:659)
       at java.util.Collections.sort(Collections.java:217)
       at io.dropwizard.configuration.ConfigurationParsingException$Builder.getSuggestions(ConfigurationParsingException.java:131)
       at io.dropwizard.configuration.ConfigurationParsingException$Builder.build(ConfigurationParsingException.java:251)
       at io.dropwizard.configuration.ConfigurationFactory.build(ConfigurationFactory.java:134)
       at io.dropwizard.configuration.ConfigurationFactory.build(ConfigurationFactory.java:77)
       at io.dropwizard.cli.ConfiguredCommand.parseConfiguration(ConfiguredCommand.java:114)
       at io.dropwizard.cli.ConfiguredCommand.run(ConfiguredCommand.java:63)
       at io.dropwizard.cli.Cli.run(Cli.java:70)
       at io.dropwizard.Application.run(Application.java:72)
```