Comment 4 for bug 1674889

Reviewed: https://review.openstack.org/448447
Committed: https://git.openstack.org/cgit/openstack/networking-ovn/commit/?id=826943a91e8ada5ac2014542faf518be4d4abb64
Submitter: Jenkins
Branch: master

commit 826943a91e8ada5ac2014542faf518be4d4abb64
Author: Dong Jun <email address hidden>
Date: Wed Mar 22 16:28:25 2017 +0800

    Fix OvnBaseConnection.get_schema_helper bug in some case

    When thread of ovn ovsdb-server is not present(e.g. kill the process),
    restart neutron-server and then start ovn ovsdb-server, neutron-server
    can no longer connect to ovn ovsdb unless I delete ovs manager manually.
    This bug is not always exists, it's caused by some recent neutron
    modification. Neutron code moved Connection.get_schema_helper() logic
    to idlutils.get_schema_helper()[1], the change affects OvnBaseConnection.
    get_schema_helper(), because enable_connection_uri() is called again.
    Use idlutils._get_schema_helper() instead of idlutils.get_schema_helper()
    to fix this bug.
    [1]https://github.com/openstack/neutron/blob/master/neutron/agent/ovsdb/native/connection.py#L123-L129

    Change-Id: I01a3a65f264bd7e080f9aa2c5e2482dbe07694f4
    Partial-Bug: #1674889
    Signed-off-by: Dong Jun <email address hidden>