.gitignore cleanup
.gitignore cleanup

Removed obsolete files/dirs
Added .coverage and covhtml
Ordered alphabetically

Change-Id: Iac10b075f318c264549ee017688eccd52deae07d

openstack/neutron-vpnaas,dougwig/x-neutron-fwaas,dougwig/x-neutron-vpnaas,citrix-openstack-build/neutron-vpnaas,flavio-fernandes/networking-odl,FedericoRessi/networking-odl,gandelman-a/neutron-lbaas,gotostack/neutron-lbaas,citrix-openstack-build/neutron-fwaas,openstack/neutron-fwaas,gandelman-a/neutron-lbaas,gandelman-a/neutron-lbaas,openstack/networking-odl,dougwig/x-neutron-lbaas,schoksey/networking-odl,gaolichuang/neutron-fwaas,gotostack/neutron-lbaas,openstack/networking-odl,gaolichuang/neutron-fwaas,mestery/x-stackforge-odl,gotostack/neutron-lbaas,CiscoSystems/networking-odl,openstack/neutron-fwaas,schoksey/networking-odl,openstack/neutron-vpnaas,FedericoRessi/networking-odl,openstack/networking-odl,citrix-openstack-build/neutron-lbaas,flavio-fernandes/networking-odl,CiscoSystems/networking-odl