Update sphinx to be compatible with readthedocs.org
Update sphinx to be compatible with readthedocs.org

JJB docs are published to readthedocs.org but fails to build because
RTD only supports a newer version of sphinx.  Updating sphinx to
version 1.3.1 so build won't fail on RTD.

depends-on: Iba92628263e20efca84aeada0e19000f4c9b1fac
Change-Id: Ia8d4033bf2def5066bda26813b41338408093481

dataxu/jenkins-job-builder,phinexus/jenkins-job-builder,linuxmaniac/jenkins-job-builder,joostvdg/jenkins-job-builder,grdryn/jenkins-job-builder,dataxu/jenkins-job-builder,twc-openstack/jenkins-job-builder,rsig/jenkins-job-builder,puppetlabs/jenkins-job-builder,david-caro/jenkins-job-builder,gforcada/jenkins-job-builder,gregsymons/jenkins-job-builder,GoodgameStudios/jenkins-job-builder,gforcada/jenkins-job-builder,onshape/jenkins-job-builder,madAndroid/jenkins-job-builder,wsoula/jenkins-job-builder,tamac-io/jenkins-job-builder,lukas-bednar/jenkins-job-builder,jenshnielsen/jenkins-job-builder,mjeanson/jenkins-job-builder,theforeman/jenkins-job-builder,OSSystems/jenkins-job-builder,twc-openstack/jenkins-job-builder,grdryn/jenkins-job-builder,phinexus/jenkins-job-builder,mjeanson/jenkins-job-builder,dataxu/jenkins-job-builder,grdryn/jenkins-job-builder,madAndroid/jenkins-job-builder,gregsymons/jenkins-job-builder,klmitch/jenkins-job-builder,david-caro/jenkins-job-builder,GoodgameStudios/jenkins-job-builder,OSSystems/jenkins-job-builder,mjeanson/jenkins-job-builder,wikimedia/integration-jenkins-job-builder,stanchan/jenkins-job-builder,wikimedia/integration-jenkins-job-builder,wikimedia/integration-jenkins-job-builder,jenshnielsen/jenkins-job-builder,klmitch/jenkins-job-builder,pyatil/jenkins-job-builder,rsig/jenkins-job-builder,simzacks/jjb,klmitch/jenkins-job-builder,pyatil/jenkins-job-builder,lukas-bednar/jenkins-job-builder,david-caro/jenkins-job-builder,linuxmaniac/jenkins-job-builder,OSSystems/jenkins-job-builder,madAndroid/jenkins-job-builder,mjeanson/jenkins-job-builder,phinexus/jenkins-job-builder,jenshnielsen/jenkins-job-builder,tamac-io/jenkins-job-builder,pyatil/jenkins-job-builder,joostvdg/jenkins-job-builder,wsoula/jenkins-job-builder,onshape/jenkins-job-builder,rsig/jenkins-job-builder,theforeman/jenkins-job-builder,lukas-bednar/jenkins-job-builder,pyatil/jenkins-job-builder,stanchan/jenkins-job-builder,linuxmaniac/jenkins-job-builder,joostvdg/jenkins-job-builder,gforcada/jenkins-job-builder,simzacks/jjb,david-caro/jenkins-job-builder,twc-openstack/jenkins-job-builder,phinexus/jenkins-job-builder,wsoula/jenkins-job-builder,theforeman/jenkins-job-builder,wsoula/jenkins-job-builder,phinexus/jenkins-job-builder,onshape/jenkins-job-builder,simzacks/jjb,stanchan/jenkins-job-builder,tamac-io/jenkins-job-builder,onshape/jenkins-job-builder,rsig/jenkins-job-builder,gforcada/jenkins-job-builder,tamac-io/jenkins-job-builder,gregsymons/jenkins-job-builder,simzacks/jjb,wikimedia/integration-jenkins-job-builder,puppetlabs/jenkins-job-builder,GoodgameStudios/jenkins-job-builder,joostvdg/jenkins-job-builder,twc-openstack/jenkins-job-builder,theforeman/jenkins-job-builder,gforcada/jenkins-job-builder,puppetlabs/jenkins-job-builder,dataxu/jenkins-job-builder,OSSystems/jenkins-job-builder,wikimedia/integration-jenkins-job-builder,puppetlabs/jenkins-job-builder,klmitch/jenkins-job-builder,linuxmaniac/jenkins-job-builder,lukas-bednar/jenkins-job-builder