Correct puppet module list check in beaker

The final check during the prep stage, where `puppet module list` is
run so that its output can be used for debugging, should run on the
current host in the loop, not the first host in the array.

Change-Id: I664f50fd323cfc0e3828f4198d10ff4a1b50b8b2

spec/spec_helper_acceptance.rb

@@ -50,7 +50,7 @@ RSpec.configure do |c|
       on host, "rm -fr #{repo}"
 
       # List modules installed to help with debugging
-      on hosts[0], puppet('module','list'), { :acceptable_exit_codes => 0 }
+      on host, puppet('module','list'), { :acceptable_exit_codes => 0 }
     end
   end
 end