Make user creation optional when creating service.

In some cases it is useful to be able to just configure
the service in Keystone and not the service user. This
is the case when e.g. a read only LDAP backend is used.
Added parameters configure_user and configure_user_role
(default to true).

Change-Id: I6b0b7e2554e982550d71d8427ce2ea94f04f55e8
Closes-Bug: 1360232
Add tuning db configs

add min_pool_size, max_pool_size, max_overflow

use the same default values as neutron project

Change-Id: I9cc7744b10be03253e1dfe1efa58278d3c8539e8
Make api_extensions_path a parameter for "neutron"

Currently, the "neutron" class does not support the direct configuration
of the "api_extensions_path" by means of a parameter. However, there is
at least one plugin -- OpenContrail -- which currently requires exactly
this parameter to be set to work. It is hence desireable to be able to
set the parameter directly from within the "neutron" class instead of
having to fiddle with "neutron_config" in local site manifests.

This commit adds the desired functionality and allows the parameter via
"api_extensions_path" to be set directly for the "neutron" class.

Change-Id: I660848100073a3a0067ffb42791bfd80b66c808e
Merge "Make user creation optional when creating service."
Merge "Add tuning db configs"
Merge "Make api_extensions_path a parameter for "neutron""