Refactor lib/neutron rootwrap conf for reuse

This change separates out the creation and permision setting for
the /etc/neutron so that it can be reused by functional test
setup in rootwrap deployment.

Change-Id: Ib2ad5b21630ac82a3d7ffc7b088600b2168f1ecd
diff --git a/lib/neutron b/lib/neutron
index 0f49476..b13e31b 100755
--- a/lib/neutron
+++ b/lib/neutron
@@ -791,15 +791,20 @@
     done
 }
 
-# _configure_neutron_common()
-# Set common config for all neutron server and agents.
-# This MUST be called before other ``_configure_neutron_*`` functions.
-function _configure_neutron_common {
+
+function _create_neutron_conf_dir {
     # Put config files in ``NEUTRON_CONF_DIR`` for everyone to find
     if [[ ! -d $NEUTRON_CONF_DIR ]]; then
         sudo mkdir -p $NEUTRON_CONF_DIR
     fi
     sudo chown $STACK_USER $NEUTRON_CONF_DIR
+}
+
+# _configure_neutron_common()
+# Set common config for all neutron server and agents.
+# This MUST be called before other ``_configure_neutron_*`` functions.
+function _configure_neutron_common {
+    _create_neutron_conf_dir
 
     cp $NEUTRON_DIR/etc/neutron.conf $NEUTRON_CONF