First round of clean-ups of imports and unused variables

Run pyflakes src/osmo_gsm_tester and then address the first
round of problems.

Change-Id: I02f1d89078dfdf37d53e2e20811bf36fb14ec3b0
diff --git a/src/osmo_gsm_tester/suite.py b/src/osmo_gsm_tester/suite.py
index 3a49574..932a6ab 100644
--- a/src/osmo_gsm_tester/suite.py
+++ b/src/osmo_gsm_tester/suite.py
@@ -21,7 +21,7 @@
 import sys
 import time
 import pprint
-from . import config, log, template, util, resource, schema, test
+from . import config, log, util, resource, test
 from .event_loop import MainLoop
 from . import osmo_nitb, osmo_hlr, osmo_mgcpgw, osmo_mgw, osmo_msc, osmo_bsc, osmo_stp, osmo_ggsn, osmo_sgsn, modem, esme, osmocon