Use latest eventlet in probe tests

Note that eventlet 0.22.0+ closes connections between requests when
it stops accepting connections.

Partial-Bug: #1792615
Change-Id: Ia8d9ab95e2aad40e8d797acc3423a917e809ffdb

test/probe/test_signals.py

@@ -62,6 +62,10 @@ class TestWSGIServerProcessHandling(unittest.TestCase):
         self.assertEqual(resp.status // 100, 4)
         resp.read()
 
+        # Start the request before reloading...
+        putrequest(conn, 'PUT', 'blah',
+                   headers={'Content-Length': len(body)})
+
         manager.reload()
 
         post_reload_pids = set(pid for server in manager.servers
@@ -72,15 +76,19 @@ class TestWSGIServerProcessHandling(unittest.TestCase):
             starting_pids, post_reload_pids)
         self.assertFalse(starting_pids & post_reload_pids, msg)
 
-        # ... and yet we can keep using the same connection!
-        putrequest(conn, 'PUT', 'blah',
-                   headers={'Content-Length': len(body)})
+        # ... and make sure we can finish what we were doing, and even
+        # start part of a new request
         conn.send(body)
         resp = conn.getresponse()
         self.assertEqual(resp.status // 100, 4)
-        resp.read()
+        # We can even read the body
+        self.assertTrue(resp.read())
 
-        # close our connection
+        # After this, we're in a funny spot. With eventlet 0.22.0, the
+        # connection's now closed, but with prior versions we could keep
+        # going indefinitely. See https://bugs.launchpad.net/swift/+bug/1792615
+
+        # Close our connection, to make sure old eventlet shuts down
         conn.close()
 
         # sanity

tools/playbooks/common/install_dependencies.yaml

@@ -18,8 +18,8 @@
     - name: installing dependencies
       yum: name={{ item }} state=present
       with_items:
-        - python-eventlet
         - python-pyeclib
+        - python-pip
         - python-nose
         - python-swiftclient
 
@@ -27,3 +27,4 @@
       pip: name={{ item }} state=present extra_args='--upgrade'
       with_items:
         - crudini
+        - eventlet