[CleanRepo] NRE when running remove-hops on azure-docs-pr

[gewarren]

Removing hops from the '.openpublishing.redirection.json' redirection file.
Unhandled exception. System.NullReferenceException: Object reference not set to an instance of an object.
at CleanRepo.DocFxRepo.RemoveRedirectHopsFromFile(FileInfo redirectsFile, Dictionary2 docsets, String rootPath) in C:\Users\gewarren\docs-tools\cleanrepo\CleanRepo\Repo.cs:line 630 at CleanRepo.DocFxRepo.RemoveAllRedirectHops() in C:\Users\gewarren\docs-tools\cleanrepo\CleanRepo\Repo.cs:line 551 at CleanRepo.Program.RunOptions(Options options) in C:\Users\gewarren\docs-tools\cleanrepo\CleanRepo\Program.cs:line 422 at CommandLine.ParserResultExtensions.WithParsed[T](ParserResult1 result, Action`1 action)
at CleanRepo.Program.Main(String[] args) in C:\Users\gewarren\docs-tools\cleanrepo\CleanRepo\Program.cs:line 41