Try to avoid hard-coding the 8091 port

We already have an attribute for this.

There are still hard-coded usages, but this commit is a first step.
Remove unused provisioner_ip template variable
Prepare for SUSE Cloud 3
Merge pull request #222 from dirkmueller/release/roxy/master

+1
Merge pull request #216 from vuntz/no-hardcoded-port

Try to avoid hard-coding the 8091 port