(PE-15351) Use -f option for 2016.2.1+ installs

Prior to this commit there was not an option for signalling a
non-interactive install to the installer.
This commit adds the new `-f` option added in
https://github.com/puppetlabs/pe-installer-shim/pull/31 to the
command line options for installation/upgrade.

Additionally, this commit will remove the `-c` parameter being
passed on upgrades from a 2016.2.0+ install, because the installer
should be able to pick up on the existing pe.conf file.

lib/beaker-pe/install/pe_utils.rb

@@ -109,7 +109,19 @@ def installer_cmd(host, opts)
             host.install_from_file("puppet-enterprise-#{version}-#{host['platform']}.swix")
           else
             pe_debug = host[:pe_debug] || opts[:pe_debug]  ? ' -D' : ''
-            "cd #{host['working_dir']}/#{host['dist']} && ./#{host['pe_installer']}#{pe_debug} #{host['pe_installer_conf_setting']}"
+            pe_cmd = "cd #{host['working_dir']}/#{host['dist']} && ./#{host['pe_installer']}#{pe_debug}"
+            if ! version_is_less(host['pe_ver'], '2016.2.1') && !(opts[:type] == :upgrade && version_is_less(host['pe_upgrade_ver'], '2016.2.1') )
+              # -f option forces non-interactive mode
+              pe_cmd += " -f"
+            end
+
+            # If there are no answer overrides, and we are doing an upgrade from 2016.2.0,
+            # we can assume there will be a valid pe.conf in /etc that we can re-use.
+            if opts[:answers].nil? && opts[:custom_answers].nil? && opts[:type] == :upgrade && !version_is_less(host['pe_ver'], '2016.2.0')
+              "#{pe_cmd}"
+            else
+              "#{pe_cmd} #{host['pe_installer_conf_setting']}"
+            end
           end
         end