Remove eventlet_hub option

The option has a default value that is not portable, and therefore the
test fails on OS like Darwin. There's actually no need to specify any
hub – no other OpenStack projects as that option – as in theory Eventlet
is smart enough to pick the best implementation available anyway.

However, since Glance only works with poll or select as a hub, let's try
them in that order. That avoids a user selecting things like 'epolls'
and expecting Glance to work, whereas it would fail.

Also remove a useless cleanup() call in the failing test as the
start_servers() method already does a cleanup itself.

Change-Id: Ia7765151ebb00cdf01e96cf39f3242899d358772

glance/common/wsgi.py

@@ -79,11 +79,6 @@ eventlet_opts = [
                help=_('The number of child process workers that will be '
                       'created to service requests. The default will be '
                       'equal to the number of CPUs available.')),
-    cfg.StrOpt('eventlet_hub', default='poll',
-               help=_('Name of eventlet hub to use. Traditionally, we have '
-                      'only supported \'poll\', however \'selects\' may be '
-                      'appropriate for some platforms. See '
-                      'http://eventlet.net/doc/hubs.html for more details.')),
     cfg.IntOpt('max_header_line', default=16384,
                help=_('Maximum line size of message headers to be accepted. '
                       'max_header_line may need to be increased when using '
@@ -197,11 +192,15 @@ def get_socket(default_port):
 
 def set_eventlet_hub():
     try:
-        eventlet.hubs.use_hub(cfg.CONF.eventlet_hub)
+        eventlet.hubs.use_hub('poll')
     except Exception:
-        msg = _("eventlet '%s' hub is not available on this platform")
+        try:
+            eventlet.hubs.use_hub('selects')
+        except Exception:
+            msg = _("eventlet 'poll' nor 'selects' hubs are available "
+                    "on this platform")
             raise exception.WorkerCreationFailure(
-            reason=msg % cfg.CONF.eventlet_hub)
+                reason=msg)
 
 
 class Server(object):

glance/tests/functional/v1/test_multiprocessing.py

@@ -54,7 +54,6 @@ class TestMultiprocessing(functional.FunctionalTest):
         Ensure an interrupt signal does not cause a respawn storm.
         See bug #978130
         """
-        self.cleanup()
         self.start_servers(**self.__dict__.copy())
 
         children = self._get_children()

glance/tests/unit/test_opts.py

@@ -102,7 +102,6 @@ class OptsTestCase(utils.BaseTestCase):
             'bind_host',
             'bind_port',
             'workers',
-            'eventlet_hub',
             'max_header_line',
             'backlog',
             'tcp_keepidle',
@@ -202,7 +201,6 @@ class OptsTestCase(utils.BaseTestCase):
             'cert_file',
             'key_file',
             'workers',
-            'eventlet_hub',
             'max_header_line',
             'flavor',
             'config_file'