Copy away output directories of failed acceptance tests. (#967)

And dump logs on travis from only failed features

.travis.yml

@@ -137,7 +137,7 @@ script:
             echo Running acceptance tests using python${pv}
             if ! PATH=.:/usr/lib/postgresql/9.6/bin:$PATH $TEST_SUITE; then
                 # output all log files when tests are failing
-                grep . features/output/*/*postgres?.*
+                grep . features/output/*_failed/*postgres?.*
                 exit 1
             fi
         fi

features/environment.py

@@ -823,3 +823,5 @@ def after_feature(context, feature):
     context.pctl.stop_all()
     shutil.rmtree(os.path.join(context.pctl.patroni_path, 'data'))
     context.dcs_ctl.cleanup_service_tree()
+    if feature.status == 'failed':
+        shutil.copytree(context.pctl.output_dir, context.pctl.output_dir + '_failed')