Use python3 for osmo_ctrl.py

It's a standalone script illustrating the use of ctrl protocol from
python. Since it's not used as a library and nothing depends on it, we
can safely switch to python3.

Change-Id: I2461dd9af67771beed5306116e8a1b0ee2285aa8
diff --git a/contrib/jenkins.sh b/contrib/jenkins.sh
index c4ddf7d..d18b19d 100755
--- a/contrib/jenkins.sh
+++ b/contrib/jenkins.sh
@@ -6,7 +6,7 @@
 
 # FIXME: remove once python 2 support is deprecated
 PY2=python2
-PY2_LIST="osmopy scripts/osmo_ctrl.py scripts/osmodumpdoc.py scripts/osmotestvty.py scripts/osmotestconfig.py"
+PY2_LIST="osmopy scripts/osmodumpdoc.py scripts/osmotestvty.py scripts/osmotestconfig.py"
 $PY2 ./setup.py install
 $PY2 tests/test_py2.py
 for f in $PY2_LIST
@@ -24,4 +24,7 @@
     $PY3 $COM_FLAGS $f
 done
 
+cd scripts
+./osmo_ctrl.py --help
+
 # TODO: add more tests