Fall back to git clone if zuul-cloner not available
Fall back to git clone if zuul-cloner not available

Allow running of the compare test on developer workstations where it is
less common for zuul-cloner to be present by falling back to using git
clone with a depth of 1 if zuul-cloner is not available.

Change-Id: Idedc726bea12fb8862cd9574d9ce17b29011c15f

stanchan/jenkins-job-builder,joostvdg/jenkins-job-builder,OSSystems/jenkins-job-builder,klmitch/jenkins-job-builder,joostvdg/jenkins-job-builder,puppetlabs/jenkins-job-builder,carroarmato0/jenkins-job-builder,twc-openstack/jenkins-job-builder,twc-openstack/jenkins-job-builder,phinexus/jenkins-job-builder,rsig/jenkins-job-builder,partkyle/jenkins-job-builder,onshape/jenkins-job-builder,phinexus/jenkins-job-builder,linuxmaniac/jenkins-job-builder,grdryn/jenkins-job-builder,carroarmato0/jenkins-job-builder,sunyi00/jenkins-job-builder,dataxu/jenkins-job-builder,lukas-bednar/jenkins-job-builder,phinexus/jenkins-job-builder,mjeanson/jenkins-job-builder,dataxu/jenkins-job-builder,klmitch/jenkins-job-builder,sebbrandt87/jenkins-job-builder,stanchan/jenkins-job-builder,theforeman/jenkins-job-builder,partkyle/jenkins-job-builder,CruGlobal/jenkins-job-builder,linuxmaniac/jenkins-job-builder,wsoula/jenkins-job-builder,wikimedia/integration-jenkins-job-builder,david-caro/jenkins-job-builder,simzacks/jjb,CruGlobal/jenkins-job-builder,simzacks/jjb,joostvdg/jenkins-job-builder,mohitsethi/jenkins-job-builder,jenshnielsen/jenkins-job-builder,sunyi00/jenkins-job-builder,sebbrandt87/jenkins-job-builder,wsoula/jenkins-job-builder,electrical/jenkins-job-builder,blaffoy/jenkins-job-builder,fuglu/jenkins-job-builder,david-caro/jenkins-job-builder,madAndroid/jenkins-job-builder,GoodgameStudios/jenkins-job-builder,mjeanson/jenkins-job-builder,wikimedia/integration-jenkins-job-builder,gregsymons/jenkins-job-builder,CruGlobal/jenkins-job-builder,gforcada/jenkins-job-builder,wsoula/jenkins-job-builder,linuxmaniac/jenkins-job-builder,klmitch/jenkins-job-builder,pyatil/jenkins-job-builder,rsig/jenkins-job-builder,pyatil/jenkins-job-builder,onshape/jenkins-job-builder,onshape/jenkins-job-builder,linuxmaniac/jenkins-job-builder,gregsymons/jenkins-job-builder,simzacks/jjb,OSSystems/jenkins-job-builder,stanchan/jenkins-job-builder,sunyi00/jenkins-job-builder,wsoula/jenkins-job-builder,carroarmato0/jenkins-job-builder,jenshnielsen/jenkins-job-builder,mohitsethi/jenkins-job-builder,tamac-io/jenkins-job-builder,mjeanson/jenkins-job-builder,lukas-bednar/jenkins-job-builder,tya/jenkins-job-builder,wikimedia/integration-jenkins-job-builder,blaffoy/jenkins-job-builder,fuglu/jenkins-job-builder,twc-openstack/jenkins-job-builder,tya/jenkins-job-builder,gforcada/jenkins-job-builder,vredchenko/jenkins-job-builder,lukas-bednar/jenkins-job-builder,onshape/jenkins-job-builder,mjeanson/jenkins-job-builder,sebbrandt87/jenkins-job-builder,simzacks/jjb,electrical/jenkins-job-builder,fuglu/jenkins-job-builder,GoodgameStudios/jenkins-job-builder,klmitch/jenkins-job-builder,lukas-bednar/jenkins-job-builder,mohitsethi/jenkins-job-builder,puppetlabs/jenkins-job-builder,david-caro/jenkins-job-builder,joostvdg/jenkins-job-builder,tya/jenkins-job-builder,GoodgameStudios/jenkins-job-builder,theforeman/jenkins-job-builder,gregsymons/jenkins-job-builder,pyatil/jenkins-job-builder,vredchenko/jenkins-job-builder,tamac-io/jenkins-job-builder,rsig/jenkins-job-builder,david-caro/jenkins-job-builder,tamac-io/jenkins-job-builder,partkyle/jenkins-job-builder,puppetlabs/jenkins-job-builder,dataxu/jenkins-job-builder,grdryn/jenkins-job-builder,gforcada/jenkins-job-builder,electrical/jenkins-job-builder,phinexus/jenkins-job-builder,wikimedia/integration-jenkins-job-builder,phinexus/jenkins-job-builder,madAndroid/jenkins-job-builder,theforeman/jenkins-job-builder,pyatil/jenkins-job-builder,gforcada/jenkins-job-builder,theforeman/jenkins-job-builder,dataxu/jenkins-job-builder,wikimedia/integration-jenkins-job-builder,rsig/jenkins-job-builder,twc-openstack/jenkins-job-builder,jenshnielsen/jenkins-job-builder,tamac-io/jenkins-job-builder,puppetlabs/jenkins-job-builder,vredchenko/jenkins-job-builder,grdryn/jenkins-job-builder,madAndroid/jenkins-job-builder,OSSystems/jenkins-job-builder,gforcada/jenkins-job-builder,OSSystems/jenkins-job-builder