homebrew formula class should be capitalized then all lowercase

Change the Formula class name of OpenCFU to Opencfu.

Run `brew create https://github.com/qgeissmann/OpenCFU/archive/3.8.11.tar.gz` for an example of the expected class name, or interactively test with `brew irb`.  [Homebrew/cmd/create.rb](https://github.com/Homebrew/homebrew/blob/master/Library/Homebrew/cmd/create.rb#L126) formats the name with `Formulary.class_s(name)`.

```ruby
irb(main):009:0> require '/usr/local/Library/Homebrew/cmd/create.rb'
irb(main):024:0> fc = FormulaCreator.new
=> #<FormulaCreator:0x007fd92aa610c0>
irb(main):026:0> fc.url = "https://github.com/qgeissmann/OpenCFU/archive/3.8.11.tar.gz"
=> "https://github.com/qgeissmann/OpenCFU/archive/3.8.11.tar.gz"
irb(main):038:0> fc.name
=> "OpenCFU"
irb(main):050:0> fc.version
=> #<Version:0x007fd92ab3f898 @version="3.8.11", @detected_from_url=true>
irb(main):053:0> fc.path
=> #<Pathname:/usr/local/Library/Formula/opencfu.rb>
irb(main):057:0> Formulary.class_s(fc.name)
=> "Opencfu"
```