Add missing tests for db.instance_type_access_* methods
Add missing tests for db.instance_type_access_* methods

There was no tests in test_db_api for instance_type_access_* methods.

Add tests to ensure that all works.
Also these tests allow us to refactor these methods.
For example add missing unique constraint on columns
(instance_type_id, project_id)

blueprint db-api-tests

Change-Id: Idfeda1685ef8c812c1211783aede15795b0d7caf

CiscoSystems/nova,takeshineshiro/nova,shahar-stratoscale/nova,petrutlucian94/nova_dev,zzicewind/nova,mahak/nova,leilihh/nova,TieWei/nova,sridevikoushik31/nova,NeCTAR-RC/nova,gooddata/openstack-nova,MountainWei/nova,akash1808/nova,cloudbase/nova-virtualbox,isyippee/nova,tanglei528/nova,whitepages/nova,jianghuaw/nova,tangfeixiong/nova,dims/nova,hanlind/nova,orbitfp7/nova,jeffrey4l/nova,jianghuaw/nova,sebrandon1/nova,devendermishrajio/nova_test_latest,barnsnake351/nova,nikesh-mahalka/nova,felixma/nova,mahak/nova,mikalstill/nova,ruslanloman/nova,adelina-t/nova,double12gzh/nova,cernops/nova,eharney/nova,tealover/nova,jeffrey4l/nova,OpenAcademy-OpenStack/nova-scheduler,Metaswitch/calico-nova,cloudbase/nova-virtualbox,angdraug/nova,shootstar/novatest,klmitch/nova,zaina/nova,mandeepdhami/nova,raildo/nova,alexandrucoman/vbox-nova-driver,zzicewind/nova,badock/nova,eonpatapon/nova,JioCloud/nova_test_latest,fnordahl/nova,Yuriy-Leonov/nova,leilihh/novaha,redhat-openstack/nova,bigswitch/nova,alaski/nova,gspilio/nova,qwefi/nova,rickerc/nova_audit,angdraug/nova,citrix-openstack-build/nova,yosshy/nova,badock/nova,virtualopensystems/nova,Stavitsky/nova,spring-week-topos/nova-week,shootstar/novatest,eonpatapon/nova,shail2810/nova,takeshineshiro/nova,vladikr/nova_drafts,bgxavier/nova,thomasem/nova,cloudbau/nova,devoid/nova,klmitch/nova,thomasem/nova,rrader/nova-docker-plugin,CCI-MOC/nova,kimjaejoong/nova,LoHChina/nova,sridevikoushik31/nova,TwinkleChawla/nova,edulramirez/nova,mikalstill/nova,openstack/nova,iuliat/nova,SUSE-Cloud/nova,JioCloud/nova,devendermishrajio/nova_test_latest,eayunstack/nova,NeCTAR-RC/nova,DirectXMan12/nova-hacking,CEG-FYP-OpenStack/scheduler,rickerc/nova_audit,cernops/nova,raildo/nova,watonyweng/nova,Francis-Liu/animated-broccoli,klmitch/nova,saleemjaveds/https-github.com-openstack-nova,rrader/nova-docker-plugin,maelnor/nova,OpenAcademy-OpenStack/nova-scheduler,saleemjaveds/https-github.com-openstack-nova,double12gzh/nova,belmiromoreira/nova,fnordahl/nova,apporc/nova,Yusuke1987/openstack_template,sacharya/nova,redhat-openstack/nova,leilihh/novaha,mahak/nova,jianghuaw/nova,ted-gould/nova,petrutlucian94/nova,JioCloud/nova,affo/nova,shail2810/nova,Metaswitch/calico-nova,blueboxgroup/nova,scripnichenko/nova,imsplitbit/nova,zhimin711/nova,vladikr/nova_drafts,tudorvio/nova,BeyondTheClouds/nova,alexandrucoman/vbox-nova-driver,DirectXMan12/nova-hacking,isyippee/nova,maelnor/nova,berrange/nova,silenceli/nova,imsplitbit/nova,petrutlucian94/nova,tealover/nova,SUSE-Cloud/nova,joker946/nova,cernops/nova,Juniper/nova,tudorvio/nova,gspilio/nova,gooddata/openstack-nova,DirectXMan12/nova-hacking,berrange/nova,yatinkumbhare/openstack-nova,mgagne/nova,tangfeixiong/nova,gooddata/openstack-nova,spring-week-topos/nova-week,hanlind/nova,bclau/nova,adelina-t/nova,projectcalico/calico-nova,rahulunair/nova,vmturbo/nova,Francis-Liu/animated-broccoli,ntt-sic/nova,CCI-MOC/nova,Brocade-OpenSource/OpenStack-DNRM-Nova,j-carpentier/nova,rahulunair/nova,j-carpentier/nova,bgxavier/nova,joker946/nova,yatinkumbhare/openstack-nova,sridevikoushik31/nova,zhimin711/nova,noironetworks/nova,CEG-FYP-OpenStack/scheduler,ewindisch/nova,akash1808/nova_test_latest,tanglei528/nova,rahulunair/nova,mmnelemane/nova,vmturbo/nova,cloudbase/nova,Stavitsky/nova,vmturbo/nova,alvarolopez/nova,ted-gould/nova,openstack/nova,sridevikoushik31/nova,eharney/nova,plumgrid/plumgrid-nova,CloudServer/nova,qwefi/nova,jianghuaw/nova,petrutlucian94/nova_dev,luogangyi/bcec-nova,virtualopensystems/nova,bclau/nova,scripnichenko/nova,vmturbo/nova,Yusuke1987/openstack_template,varunarya10/nova_test_latest,varunarya10/nova_test_latest,Tehsmash/nova,watonyweng/nova,plumgrid/plumgrid-nova,Yuriy-Leonov/nova,yosshy/nova,Juniper/nova,tianweizhang/nova,belmiromoreira/nova,Juniper/nova,dims/nova,edulramirez/nova,openstack/nova,phenoxim/nova,cloudbau/nova,gspilio/nova,bigswitch/nova,felixma/nova,JianyuWang/nova,BeyondTheClouds/nova,luogangyi/bcec-nova,akash1808/nova_test_latest,rajalokan/nova,mgagne/nova,BeyondTheClouds/nova,akash1808/nova,devoid/nova,rajalokan/nova,mmnelemane/nova,alvarolopez/nova,citrix-openstack-build/nova,apporc/nova,zaina/nova,cloudbase/nova,LoHChina/nova,viggates/nova,gooddata/openstack-nova,blueboxgroup/nova,Tehsmash/nova,sebrandon1/nova,rajalokan/nova,iuliat/nova,ruslanloman/nova,alaski/nova,CloudServer/nova,nikesh-mahalka/nova,sebrandon1/nova,mandeepdhami/nova,shahar-stratoscale/nova,orbitfp7/nova,leilihh/nova,viggates/nova,rajalokan/nova,kimjaejoong/nova,silenceli/nova,hanlind/nova,phenoxim/nova,devendermishrajio/nova,dawnpower/nova,TieWei/nova,Brocade-OpenSource/OpenStack-DNRM-Nova,cloudbase/nova,cyx1231st/nova,noironetworks/nova,TwinkleChawla/nova,cyx1231st/nova,mikalstill/nova,CiscoSystems/nova,Juniper/nova,devendermishrajio/nova,klmitch/nova,JianyuWang/nova,MountainWei/nova,projectcalico/calico-nova,JioCloud/nova_test_latest,barnsnake351/nova,whitepages/nova,tianweizhang/nova,ewindisch/nova,ntt-sic/nova,eayunstack/nova,affo/nova,dawnpower/nova,sacharya/nova