Formula: mirrors are always non-nil
Formula: mirrors are always non-nil

Since 3ee9b7bd88a2d9017cdf005b10567a1d6d8ec211 ("SoftwareSpec:
initialize @mirrors"), @active_spec.mirrors will always be non-nil.

Signed-off-by: Jack Nagel <43386ce32af96f5c56f2a88e458cb94cebee3751@gmail.com>

nandub/brew,JCount/brew,zmwangx/brew,EricFromCanada/brew,aw1621107/brew,vitorgalvao/brew,sjackman/homebrew,DomT4/brew,reelsense/brew,pseudocody/brew,bfontaine/brew,aw1621107/brew,AnastasiaSulyagina/brew,EricFromCanada/brew,mistydemeo/homebrew,gordonmcshane/homebrew,gregory-nisbet/brew,reelsense/brew,maxim-belkin/brew,claui/brew,AnastasiaSulyagina/brew,bfontaine/brew,nandub/brew,Linuxbrew/brew,palxex/brew,reitermarkus/brew,toonetown/homebrew,JCount/brew,nandub/brew,reitermarkus/brew,konqui/brew,konqui/brew,tonyg/homebrew,gregory-nisbet/brew,pseudocody/brew,mahori/brew,DomT4/brew,reelsense/brew,MikeMcQuaid/brew,MikeMcQuaid/brew,amar-laksh/brew_sudo,konqui/brew,muellermartin/dist,vitorgalvao/brew,JCount/brew,palxex/brew,Linuxbrew/brew,ilovezfs/brew,DomT4/brew,rwhogg/brew,palxex/brew,rwhogg/brew,mistydemeo/homebrew,ilovezfs/brew,claui/brew,Homebrew/brew,ilovezfs/brew,jmsundar/brew,sjackman/homebrew,Homebrew/brew,muellermartin/dist,maxim-belkin/brew,vitorgalvao/brew,hanxue/linuxbrew,alyssais/brew,zmwangx/brew,nandub/brew,muellermartin/dist,konqui/brew,mistydemeo/homebrew,AnastasiaSulyagina/brew,mahori/brew,aw1621107/brew,mahori/brew,maxim-belkin/brew,alyssais/brew,alyssais/brew,gordonmcshane/homebrew,mgrimes/brew,MikeMcQuaid/brew,rwhogg/brew,amar-laksh/brew_sudo,reitermarkus/brew,EricFromCanada/brew,claui/brew,jmsundar/brew,hanxue/linuxbrew,EricFromCanada/brew,mgrimes/brew,staticfloat/brew,bfontaine/brew,pseudocody/brew,hanxue/linuxbrew,Linuxbrew/brew,mahori/brew,Homebrew/brew,tonyg/homebrew,sjackman/homebrew,gordonmcshane/homebrew,Linuxbrew/brew,zmwangx/brew,staticfloat/brew,Homebrew/brew,DomT4/brew,MikeMcQuaid/brew,vitorgalvao/brew,claui/brew,mgrimes/brew,amar-laksh/brew_sudo,gregory-nisbet/brew,jmsundar/brew,staticfloat/brew,toonetown/homebrew,JCount/brew,toonetown/homebrew,reitermarkus/brew,tonyg/homebrew,sjackman/homebrew