Download update center metadata every time
Download update center metadata every time

When not specifying a version in `jenkins_plugin`
Previous behavior caused cookbook to downgrade plugins (effectively freezing the latest at the first chef run)
New behavior is to upgrade plugins to latest
Also caused bugs when specifying a version higher than was available at first chef run

opscode-cookbooks/jenkins,mknapik/jenkins,j-c-h-e-n-g/jenkins,autoclone/jenkins-cookbook,gshively11/jenkins,rexut/opscode-cookbooks-jenkins,cru-Luis-Rodriguez/jenkins,autoclone/iptables,gshively11/jenkins,autoclone/iptables,Dispader/jenkins,cru-Luis-Rodriguez/jenkins,bhalothia/jenkins,Sauraus/jenkins,chef-cookbooks/jenkins,autoclone/jenkins,juliandunn/jenkins,Piousbox-cookbooks/jenkins,autoclone/jenkins,autoclone/jenkins-cookbook,cru-Luis-Rodriguez/jenkins,dshvedchenko/jenkins,dshvedchenko/jenkins,martinb3-cookbooks/jenkins,RobertNorthard/jenkins,martinb3-cookbooks/jenkins,samdunne/jenkins,juliandunn/jenkins,Dispader/jenkins,dshvedchenko/jenkins,StephenKing/chef-cookbook-jenkins,daften/cookbook-jenkins,rchekaluk/jenkins,b-dean/jenkins,samdunne/jenkins,mlongob/jenkins,Piousbox-cookbooks/jenkins,j-c-h-e-n-g/jenkins,b-dean/jenkins,developerinlondon/jenkins,umar85/jenkins,Sauraus/jenkins,Tiger66639/jenkins,j-c-h-e-n-g/jenkins,StephenKing/chef-cookbook-jenkins,samdunne/jenkins,Tiger66639/jenkins,developerinlondon/jenkins,b-dean/jenkins,chef-cookbooks/jenkins,mlongob/jenkins,gshively11/jenkins,developerinlondon/jenkins,rexut/opscode-cookbooks-jenkins,rexut/opscode-cookbooks-jenkins,RobertNorthard/jenkins,autoclone/iptables,mknapik/jenkins,umar85/jenkins,juliandunn/jenkins,daften/cookbook-jenkins,Sauraus/jenkins,bhalothia/jenkins,Piousbox-cookbooks/jenkins,RobertNorthard/jenkins,rchekaluk/jenkins,Dispader/jenkins,daften/cookbook-jenkins,opscode-cookbooks/jenkins,rchekaluk/jenkins,StephenKing/chef-cookbook-jenkins,autoclone/jenkins-cookbook,umar85/jenkins,autoclone/jenkins,mlongob/jenkins,bhalothia/jenkins,mknapik/jenkins,martinb3-cookbooks/jenkins,opscode-cookbooks/jenkins,chef-cookbooks/jenkins,Tiger66639/jenkins