travis: Try to fix docutils setup on Linux
travis: Try to fix docutils setup on Linux

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