info: Fix style: Use a guard clause
info: Fix style: Use a guard clause

Fix the style error:
Library/Homebrew/cmd/info.rb:88:7: C:
Use a guard clause instead of wrapping the code inside a conditional expression.

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