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/smsc.py b/src/osmo_gsm_tester/smsc.py
index 1a0859c..d154801 100644
--- a/src/osmo_gsm_tester/smsc.py
+++ b/src/osmo_gsm_tester/smsc.py
@@ -17,7 +17,7 @@
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-from . import log, config, util, template, process
+from . import log, config
 
 class Smsc: