Silently missing new bottle when original bottle block has less than two expressions

[easoncxz]

Turns out the Parser::AST::Node tree structure is different for

bottle do
  root_url "whatever"
end

vs

bottle do
  foobar
  root_url "whatever"
end

One is like

(block
  (send nil :bottle)
  (args)
  (send nil :root_url
    (str "https://dl.bintray.com/easoncxz/homebrew-bottles")))

While the other is like

 (block
  (send nil :bottle)
  (args)
  (begin
    (send nil :cellar
      (sym :any_skip_relocation))
    (send nil :rebuild
      (int 1))
    (send nil :root_url
      (str "https://dl.bintray.com/easoncxz/homebrew-bottles"))
    (send nil :sha256
      (hash
        (pair
          (str "4be7efbbfb251b46a860080b753bd280b36726e1d8b7815893e35354ae33f730")
          (sym :yosemite))))))

Notice that an extra layer of (:begin ...) appears if there are more than one expression.