Custom LLDP driver may not be able to set system name

[Steven Webster]

Brief Description
-----------------
If a user implements a custom LLDP agent driver and has more than one LLDP agent driver configured in the system, only the first driver in the list will get called for certain operations such as setting the system name, updating (refresh), or clearing the agents / neighbours.

Severity
--------
Minor

Steps to Reproduce
------------------
1) implement a custom LLDP agent driver
2) configure the sysinv.conf [lldp] section to have drivers=lldpd,custom
3) configure the system name vi system modify --name <newname>
4) observe that the LLDP PDUs for the custom driver does not pick up the new name

Expected Behavior
------------------
The second driver should cause LLDP PDUs to contain the new system name.

Actual Behavior
----------------
The second driver does not send the updated system name.

Reproducibility
---------------
Every time

System Configuration
--------------------
Multi-node system

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/611390

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/611390
Committed: https://git.openstack.org/cgit/openstack/stx-config/commit/?id=6847dd0c43fd2da1590ec7be798c0aca598570e5
Submitter: Zuul
Branch: master

commit 6847dd0c43fd2da1590ec7be798c0aca598570e5
Author: Steven Webster <email address hidden>
Date: Wed Oct 17 11:14:02 2018 -0400

    Fix LLDP driver manager call drivers routine

    If a user configures more than one type of LLDP agent driver, only
    the first will get called by the _call_drivers routine.

    This would affect calls to update, configure the system name,
    or clear agents / neighbours.

    Closes-Bug: #1798402
    Change-Id: I2439f5d738592a909b1703d18a0550439aa2642f
    Signed-off-by: Steven Webster <email address hidden>