formula_installer: exclude more from build-from-source warning.
formula_installer: exclude more from build-from-source warning.

We should only complain when installing requested formulae that aren't
currently installed.

JCount/brew,EricFromCanada/brew,nandub/brew,JCount/brew,MikeMcQuaid/brew,claui/brew,sjackman/homebrew,EricFromCanada/brew,vitorgalvao/brew,vitorgalvao/brew,EricFromCanada/brew,claui/brew,Homebrew/brew,konqui/brew,MikeMcQuaid/brew,vitorgalvao/brew,vitorgalvao/brew,MikeMcQuaid/brew,Homebrew/brew,EricFromCanada/brew,Homebrew/brew,claui/brew,sjackman/homebrew,konqui/brew,JCount/brew,Homebrew/brew,sjackman/homebrew,nandub/brew,nandub/brew,nandub/brew,konqui/brew,konqui/brew,claui/brew,MikeMcQuaid/brew,sjackman/homebrew,JCount/brew