commands: Remove ERROR on missing baseURL
commands: Remove ERROR on missing baseURL

That logic fails in multi-host mode when no baseURL is set on top level.

Fixes #4397

gohugoio/hugo,anthonyfok/hugo,anthonyfok/hugo,fedelibre/hugo,mdhender/hugo,mdhender/hugo,fedelibre/hugo,mdhender/hugo,anthonyfok/hugo,fedelibre/hugo,fedelibre/hugo,gohugoio/hugo,gohugoio/hugo,mdhender/hugo