Add update-server URL to check-for-updates error message
Add update-server URL to check-for-updates error message

I was running into an issue where, when my server was starting up,
it was failing to connect to the server on `check-for-updates`.
The error message that showed up in the logs wasn't entirely
intuitive; adding the URL to it makes it at least a bit more clear.

grimradical/puppetdb,waynr/puppetdb,wkalt/puppetdb,grimradical/puppetdb,grimradical/puppetdb,rbrw/puppetdb,kbarber/puppetdb,senior/puppetdb,waynr/puppetdb,jantman/puppetdb,kbarber/puppetdb,ajroetker/puppetdb,kbrezina/puppetdb,waynr/puppetdb,highb/puppetdb,melissa/puppetdb,nfagerlund/puppetdb,mullr/puppetdb,cprice404/puppetdb,cprice404/puppetdb,ajroetker/puppetdb,nfagerlund/puppetdb,johnduarte/puppetdb,kbrezina/puppetdb,jantman/puppetdb,mullr/puppetdb,waynr/puppetdb,nfagerlund/puppetdb,grimradical/puppetdb,ajroetker/puppetdb,shrug/puppetdb,mullr/puppetdb,rbrw/puppetdb,wkalt/puppetdb,mullr/puppetdb,github/puppetlabs-puppetdb,rbrw/puppetdb,puppetlabs/puppetdb,shrug/puppetdb,johnduarte/puppetdb,senior/puppetdb,highb/puppetdb,github/puppetlabs-puppetdb,johnduarte/puppetdb,shrug/puppetdb,puppetlabs/puppetdb,cprice404/puppetdb,melissa/puppetdb,highb/puppetdb,puppetlabs/puppetdb,johnduarte/puppetdb,senior/puppetdb,highb/puppetdb,kbrezina/puppetdb,senior/puppetdb,kbarber/puppetdb,melissa/puppetdb,shrug/puppetdb,wkalt/puppetdb,mullr/puppetdb,github/puppetlabs-puppetdb,rbrw/puppetdb,kbarber/puppetdb,ajroetker/puppetdb,rbrw/puppetdb,wkalt/puppetdb,kbrezina/puppetdb,jantman/puppetdb,puppetlabs/puppetdb,puppetlabs/puppetdb