Update ctrl command parsing for python3

* make parse() return command id in addition to variable name and value
* introduce parse_kv() wrapper which ignores that id and use it instead
  of old parse()
* make parse() compatible with python3 where we got bytes, not string
  from the socket so we have to decode it properly before using split()
* expand test_py3.py with simply asyn server which verifies that
  osmo_ctrl.py works properly

Change-Id: I599f9f5a18109929f59386ab4416b8bfd75c74d1
diff --git a/contrib/jenkins.sh b/contrib/jenkins.sh
index d18b19d..9734549 100755
--- a/contrib/jenkins.sh
+++ b/contrib/jenkins.sh
@@ -24,7 +24,7 @@
     $PY3 $COM_FLAGS $f
 done
 
-cd scripts
-./osmo_ctrl.py --help
+# Run async server which tests scripts/osmo_ctrl.py interaction
+$PY3 tests/test_py3.py
 
 # TODO: add more tests