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/bts_osmo.py b/src/osmo_gsm_tester/bts_osmo.py
index 89572ec..9105c28 100644
--- a/src/osmo_gsm_tester/bts_osmo.py
+++ b/src/osmo_gsm_tester/bts_osmo.py
@@ -18,10 +18,9 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 import os
-import pprint
 import tempfile
 from abc import ABCMeta, abstractmethod
-from . import log, config, util, template, process, bts, pcu_osmo
+from . import log, bts, pcu_osmo
 
 class OsmoBts(bts.Bts, metaclass=ABCMeta):