Cleanup sysinv tox py27 warnings

When tox is run for sysinv there are several warnings displayed.
  python-rpm package -  that package is now mocked out.
  pecan setup - required the debug flag to be set.

Also, the concurrency override was a testr setting and had
no effect on stestr.

Story: 2004515
Task: 33525
Change-Id: Idf32ab57102d019921bee26cda12632a26ab342d
Signed-off-by: Al Bailey <Al.Bailey@windriver.com>

sysinv/sysinv/sysinv/.stestr.conf

@@ -1,5 +1,4 @@
 [DEFAULT]
 test_path=./sysinv/tests
 top_dir=./sysinv
-# Default concurrency is 5.
-test_run_concurrency=echo 5
+#parallel_class=True

sysinv/sysinv/sysinv/sysinv/tests/api/base.py

@@ -65,6 +65,9 @@ class FunctionalTest(base.TestCase):
         # Determine where we are so we can set up paths in the config
         root_dir = self.path_get()
 
+        # pecan warns: `static_root` is only used when `debug` is True
+        # which is set by CONF.debug
+        cfg.CONF.set_override("debug", True)
         self.config = {
             'app': {
                 'root': 'sysinv.api.controllers.root.RootController',

sysinv/sysinv/sysinv/sysinv/tests/base.py

@@ -52,6 +52,7 @@ _DB_CACHE = None
 logging.setup('sysinv')
 
 sys.modules['fm_core'] = mock.Mock()
+sys.modules['rpm'] = mock.Mock()
 
 
 class Database(fixtures.Fixture):