Generating completion scripts requires Swiftly to be initialized

[SimplyDanny]

Running swiftly --generate-completion-script when Swiftly has not yet been initialized leads to:

Could not load swiftly's configuration file at /Users/brew/.swiftly/config.json.
  
To begin using swiftly you can install it: 'swiftly init'.

I feel initialization shouldn't be a requirement for shell completion to be generated. Is there a reason for that?

This is currently blocking the PR that tries to automate this task during installation with Homebrew.

[cmcgee1024]

@SimplyDanny this flag should be added to the list of exclusions for requiring swiftly to be initialized. There's no reason why generating the command-line completions should require initialization.