Further fixes to for salt-ssh test under heavy load

This makes some further tweaks to make the test more stable under heavy
load. Firstly, the background job sleeps longer, and secondly, we make
up to 3 attempts run state.running instead of just the one, in case our
first attempt was too early. It also uses threading to make the job
sleep, since the method of adding a & to the command seemed to be
producing intermittent failures with returning clean JSON.

salt/utils/thin.py

@@ -535,6 +535,7 @@ def gen_min(cachedir, extra_mods='', overwrite=False, so_mods='',
         'salt/modules/test.py',
         'salt/modules/selinux.py',
         'salt/modules/cmdmod.py',
+        'salt/modules/saltutil.py',
         'salt/minion.py',
         'salt/pillar',
         'salt/pillar/__init__.py',

tests/integration/files/file/base/running.sls

@@ -1,4 +1,4 @@
 sleep_running:
   module.run:
     - name: test.sleep
-    - length: 10
+    - length: 20

tests/integration/ssh/test_state.py

@@ -4,6 +4,7 @@
 from __future__ import absolute_import
 import os
 import shutil
+import threading
 import time
 
 # Import Salt Testing Libs
@@ -13,6 +14,7 @@ from tests.support.unit import skipIf
 
 # Import Salt Libs
 from salt.ext import six
+from salt.ext.six.moves import range  # pylint: disable=redefined-builtin
 
 SSH_SLS = 'ssh_state_tests'
 SSH_SLS_FILE = '/tmp/test'
@@ -166,19 +168,34 @@ class SSHStateTest(SSHCase):
         '''
         test state.running with salt-ssh
         '''
-        start_sls = self.run_function('state.sls', ['running', '&'],
-                                      wipe=False)
-        time.sleep(8)
-        get_sls = self.run_function('state.running', wipe=False)
-        ret = 'The function "state.pkg" is running as'
-        self.assertIn(ret, ' '.join(get_sls))
+        def _run_in_background():
+            self.run_function('state.sls', ['running'], wipe=False)
+
+        bg_thread = threading.Thread(target=_run_in_background)
+        bg_thread.start()
+
+        expected = 'The function "state.pkg" is running as'
+        for _ in range(3):
+            time.sleep(5)
+            get_sls = self.run_function('state.running', wipe=False)
+            try:
+                self.assertIn(expected, ' '.join(get_sls))
+            except AssertionError:
+                pass
+            else:
+                # We found the expected return
+                break
+        else:
+            self.fail(
+                'Did not find \'{0}\' in state.running return'.format(expected)
+            )
 
         # make sure we wait until the earlier state is complete
         future = time.time() + 120
         while True:
             if time.time() > future:
                 break
-            if ret not in ' '.join(self.run_function('state.running', wipe=False)):
+            if expected not in ' '.join(self.run_function('state.running', wipe=False)):
                 break
 
     def tearDown(self):