Use _handle_not_found_exception in neutron resources

[Sergey Kraynev]

Currently base class NeutronResource in neutron.py has function _handle_not_found_exception.

In other child neutron resources we have duplicate code of current function.
So, I offer use existed function in these places.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/65888

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/65888
Committed: https://git.openstack.org/cgit/openstack/heat/commit/?id=37200ba7fe857d37ff06080d9785f303abb403c1
Submitter: Jenkins
Branch: master

commit 37200ba7fe857d37ff06080d9785f303abb403c1
Author: Sergey Kraynev <email address hidden>
Date: Fri Jan 10 03:04:07 2014 -0500

    Using _handle_not_found_exception in resources

    This patch replace duplicate code in neutron resources on
    function _handle_not_found_exception defined in parent class.

    Change-Id: I7f86f52a8d00590c83aad01bc26507c78f01ddbb
    Closes-bug: #1267729