(maint) Handle case where agent and server are on the same host

The test sets the vendormoduledir so that compilation succeeds and
expects the agent to fail, since the customtype was never pluginsynced.
Override vendormoduledir on the agent so the test works in either case.

Author: joshcooper

acceptance/tests/agent/agent_fails_with_unknown_resource.rb

@@ -68,7 +68,9 @@ def refresh
           agent.rm_rf(vendor_modules_path)
         end
 
-        on(agent, puppet('agent', '-t', '--environment', tmp_environment), acceptable_exit_codes: [1]) do |result|  
+        # override vendormoduledir in case agent and server are on the same host
+        agent_dir = get_test_file_path(agent, 'vendormodulepath')
+        on(agent, puppet('agent', '-t', '--environment', tmp_environment, '--vendormoduledir', agent_dir), acceptable_exit_codes: [1]) do |result|
           assert_match(/Error: Failed to apply catalog: Resource type 'Mycustomtype' was not found/, result.stderr)
         end
       end