Remove two exceptions already in neutron-lib
Remove two exceptions already in neutron-lib

Since the InvalidIpForNetwork and InvalidContentType exception definitions
have already defined in neutron-lib, we don't need them in Neutron code.

Change-Id: I35afdf75a5e1fcb100f13f9ec3a0282192111e76
Signed-off-by: liusheng <a7600610d25aa82a497bd6865d623c962fd0c74a@huawei.com>

noironetworks/neutron,sebrandon1/neutron,bigswitch/neutron,igor-toga/local-snat,cloudbase/neutron,openstack/neutron,mahak/neutron,noironetworks/neutron,sebrandon1/neutron,huntxu/neutron,eayunstack/neutron,mahak/neutron,igor-toga/local-snat,cloudbase/neutron,bigswitch/neutron,mahak/neutron,eayunstack/neutron,openstack/neutron,openstack/neutron,huntxu/neutron