Stop building Chef Infra Server on SLES 11
Stop building Chef Infra Server on SLES 11

As of March 31st 2019, SLES 11 is no longer generally supported. Per our
support process we will no longer officially support SLES 11.

See https://docs.chef.io/platforms.html#platform-end-of-life-policy

Signed-off-by: Seth Chisamore <215bfe682a8577a270cfd5ba940454500e137d63@chef.io>

chef/chef-server,chef/chef-server,chef/chef-server,chef/chef-server,chef/chef-server,chef/chef-server