improve python 3 compatibility

docker_build.py

@@ -11,7 +11,7 @@
 from subprocess import call
 import sys
 
-import ConfigParser
+from six.moves import configparser
 
 import docker  # apt python-docker (1.9) or pip install docker
 
@@ -101,7 +101,7 @@
     dev = nmspc.dev
     push = nmspc.push
 
-    c = ConfigParser.ConfigParser()
+    c = configparser.ConfigParser()
     if not os.path.exists(setup_path):
         logging.fatal('Missing %s', setup_path)
         return 12