formulary: use formula path when loading from bottle

[SeekingMeaning]

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This makes a small but significant change to Formulary::BottleLoader - the call to Formulary.from_contents should be given the path to the formula instead of the bottle file path. This allows the formula tap to be properly determined as it uses the path argument to make this determination.

As far as I can tell, passing @bottle_filename was having no effect as usually this would be an arbitrary filepath that would make Tap.from_path return nil

For example,

• path could be /usr/local/Homebrew/Library/Taps/myorg/mytap2/myformula.rb, and
• @bottle_filename could be ~/Downloads/bottles/myformula--0.0.1.catalina.bottle.tar.gz

This patch allows a formula that has the same name as another formula in a different tap to be installed from a bottle file.

Before:

$ brew install myformula--0.0.1.catalina.bottle.tar.gz
Error: Formulae found in multiple taps: 
       * myorg/mytap1/myformula
       * myorg/mytap2/myformula

Please use the fully-qualified name (e.g. myorg/mytap1/myformula) to refer to the formula.

After:

$ brew install myformula--0.0.1.catalina.bottle.tar.gz
==> Installing myformula from myorg/mytap2/myformula
🍺  /usr/local/Cellar/myformula/0.0.1: 42 files, 123.4KB

[MikeMcQuaid]

Very nice, thanks @SeekingMeaning!