Do not fail if there is only blog post in the future
Do not fail if there is only blog post in the future

This manifest with the following traceback :
       error  build/blog/feed.xml
  undefined method `date' for nil:NilClass
  /home/fedora/atomic-site/source/feed.xml.builder:10:in `block (2 levels) in singleton class'
  /home/fedora/.gem/ruby/gems/builder-3.2.2/lib/builder/xmlbase.rb:175:in `call'
  /home/fedora/.gem/ruby/gems/builder-3.2.2/lib/builder/xmlbase.rb:175:in `_nested_structures'
  /home/fedora/.gem/ruby/gems/builder-3.2.2/lib/builder/xmlbase.rb:68:in `tag!'
  /home/fedora/.gem/ruby/gems/builder-3.2.2/lib/builder/xmlbase.rb:93:in `method_missing

The cause is that blog.articles.first will be Nil if there is no blog
post and yet the blog exist ( since there is article to be published )

anoopcs9/glusterweb,apevec/website,yazug/rdo-website,yazug/rdo-website,anoopcs9/glusterweb,TomasTomecek/atomic-site,cdrage/atomic-site,weshayutin/website,dwlehman/blivet-web,vaneldik/website,jtokar/ovirt-site,jasonbrooks/ovirt-stg,rafaelmartins/ovirt-site,rafaelmartins/ovirt-site,anoopcs9/glusterweb,PeterDaveHello/glusterweb,SaravanaStorageNetwork/glusterweb,thatdocslady/ovirt-site,dtantsur/website,hguemar/website,gluster/glusterweb,mscherer/glusterweb,thatdocslady/ovirt-site,nzwulfin/atomic-site,weshayutin/website,aweiteka/atomic-site,jtokar/ovirt-site,goern/atomic-site,wking/atomic-site,pwnall/atomic-site,OSAS/middleman-planet,mscherer/glusterweb,pwnall/atomic-site,dwlehman/blivet-web,wking/atomic-site,mscherer/glusterweb,aweiteka/atomic-site,gluster/glusterweb,dtantsur/website,OSAS/middleman-planet,sachidanandaurs/planet-gluster,fmpwizard/atomic-site,coolsvap/website,weshayutin/website,msvbhat/planet-gluster,subecho/website,dwlehman/blivet-web,mrjoshuap/atomic-site,shishir-a412ed/atomic-site,vaneldik/website,kshlm/glusterweb,yazug/rdo-website,jtokar/ovirt-site,msvbhat/planet-gluster,kshlm/glusterweb,kshlm/glusterweb,nzwulfin/atomic-site,TomasTomecek/atomic-site,cdrage/atomic-site,sachidanandaurs/planet-gluster,bexelbie/atomic-site,gluster/glusterweb,SaravanaStorageNetwork/glusterweb,PeterDaveHello/glusterweb,rafaelmartins/ovirt-site,fmpwizard/atomic-site,thatdocslady/ovirt-site,goern/atomic-site,subecho/website,SaravanaStorageNetwork/glusterweb,sachidanandaurs/planet-gluster,cdrage/atomic-site,gluster/glusterweb,apevec/website,thatdocslady/ovirt-site,AsherBond/gluster-site,AsherBond/gluster-site,jasonbrooks/ovirt-stg,shishir-a412ed/atomic-site,jasonbrooks/ovirt-stg,rafaelmartins/ovirt-site,weshayutin/website,shishir-a412ed/atomic-site,SaravanaStorageNetwork/glusterweb,PeterDaveHello/glusterweb,ManageIQ/planet.manageiq.org,dwlehman/blivet-web,nzwulfin/atomic-site,yazug/rdo-website,fmpwizard/atomic-site,kshlm/glusterweb,TomasTomecek/atomic-site,cdrage/atomic-site,subecho/website,jtokar/ovirt-site,bexelbie/atomic-site,ManageIQ/planet.manageiq.org,subecho/website,hguemar/website,bexelbie/atomic-site,vaneldik/website,bexelbie/atomic-site,mrjoshuap/atomic-site,coolsvap/website,fmpwizard/atomic-site,jasonbrooks/ovirt-stg,vaneldik/website,aweiteka/atomic-site,sachidanandaurs/planet-gluster,hguemar/website,pwnall/atomic-site,anoopcs9/glusterweb,mrjoshuap/atomic-site,goern/atomic-site,msvbhat/planet-gluster,aweiteka/atomic-site,pwnall/atomic-site,OSAS/middleman-planet,hguemar/website,apevec/website,weshayutin/website,nzwulfin/atomic-site,coolsvap/website,coolsvap/website,PeterDaveHello/glusterweb,msvbhat/planet-gluster,ManageIQ/planet.manageiq.org,apevec/website,TomasTomecek/atomic-site,hguemar/website,nzwulfin/atomic-site,shishir-a412ed/atomic-site,OSAS/middleman-planet,apevec/website,dtantsur/website,wking/atomic-site,AsherBond/gluster-site,mrjoshuap/atomic-site,dtantsur/website,goern/atomic-site,wking/atomic-site,mscherer/glusterweb,bexelbie/atomic-site,ManageIQ/planet.manageiq.org