Extend test timeout to 120s

This may help tests pass when running under 4 vcpus.  Also:

A following change adds more git operations to most of the tests.
This is because each git repo must be listed in the tenant config
file, and many tests share a tenant config with quite a number
of repos which they don't use.  We should improve the tests so that
they don't operate on repos that they don't need, but that will
take some work.

Change-Id: I91a327968359b3650fbe0477e99dc274a1fb6266
diff --git a/tests/base.py b/tests/base.py
index a0a986a..0a2c71a 100755
--- a/tests/base.py
+++ b/tests/base.py
@@ -1135,7 +1135,7 @@
 
 class BaseTestCase(testtools.TestCase):
     log = logging.getLogger("zuul.test")
-    wait_timeout = 20
+    wait_timeout = 30
 
     def attachLogs(self, *args):
         def reader():