Issue803

updated neutron for better rhel support
When using a rhel or rhel based system, the package installation
of neutron, when installing via RDO, drops the file
"/usr/share/neutron/neutron-dist.conf" which adds unexpected variables
to the neutron configuration.  The pull requests makes the file
"/etc/neutron/neutron.conf" the one source of truth.

To accomodate some additional configuration which was in service in the
RHEL configuration file the following attributes were added.

```
default["neutron"]["database"]["max_overflow"] = 20
default["neutron"]["database"]["pool_timeout"] = 10
```

These attributes mirror the openstack defaults from upstream
neutron.conf example.