Homebrew/homebrew — pull request #32814 by jconley (2014-09-30 16:26:05+00:00)
Title: requirement default_formula tries to install even when satisfied?==true

In creating #31975 and #32203, I used `--build-from-source` to test compilation instead of using bottles.
Now that these are committed, I cannot install/upgrade any formula with a bottle that `depends_on :osxfuse` while binary osxfuse is installed.
Some logic is triggering the install of the default_formula from OsxfuseDependency even when satisfied?==true. This in turn tries to install homebrew osxfuse which `depends_on ConflictsWithBinaryOsxfuse` and fails the install/upgrade since the binary install is already present.

The logic governing this most recently changed in formula_installer.rb#install_requirement_default_formula? and pour_bottle? in a0a93f1b3b7b2be9b8a319be91086ffe220f8e32.
It seems Requirement.pour_bottle? is never called after this change? (although no Requirement seems to be using the pour_bottle? override before now)

I don't have any background on the previous change (python related) or how to test what it enabled/fixed, but have attempted some changes and would like comment/review. @mikemcquaid
I also discovered/implemented OsxfuseDependency.pour_bottle?

To reproduce:
`brew uninstall osxfuse`
`brew install brew-cask`
`brew cask install osxfuse`
`brew install tup`