Fix an issue with --debug and _dump on Ruby 1.8.7

[claui]

This is a very minor issue I bumped into while working on brew cask search. For casks that have an installer stanza, the internal command brew cask _dump would fail on Ruby 1.8.7. One example where this occurs is the Cask adobe-air.

Assuming both rbenv and 1.8.7-p375 installed, the issue can be reproduced like so:

RBENV_VERSION=1.8.7-p375 HOMEBREW_BREW_FILE=/usr/local/bin/brew ruby /usr/local/Library/brew.rb /usr/local/bin/brew-cask _dump adobe-air

This would result in the following error:

Warning: adobe-air was not found or would not load: wrong number of arguments (1 for 0)
Error: nothing to dump
/usr/local/Cellar/brew-cask/0.49.0/rubylib/cask/cli/internal_dump.rb:8:in `run'
/usr/local/Cellar/brew-cask/0.49.0/rubylib/cask/cli.rb:81:in `run_command'
/usr/local/Cellar/brew-cask/0.49.0/rubylib/cask/cli.rb:121:in `process'
/usr/local/bin/brew-cask.rb:42
/usr/local/Library/brew.rb:59:in `require'
/usr/local/Library/brew.rb:59:in `require?'
/usr/local/Library/brew.rb:118

[rolandwalker]

Right, because installer is just a species of artifact, and artifacts are dumped together. Those methods look like copypasta (from me).

Perhaps the class name Cask::DSL::Installer could be changed to clarify that it is an artifact. Then again, all the other DSL classes are named exactly after the stanza name.

Certainly we could gain clarity by changing/breaking apart Cask::Installer (lib/cask/installer.rb).

I hope to revisit _dump soon to define a static downstream JSON Cask representation based on DSL 1.0. The YAML should be changed as well, to represent the entire Cask within a single structure.