Add serializer capability to fake_notifier.
Add serializer capability to fake_notifier.

With the change to oslo.messaging.notify.Notifier, we have
introduced the serializer plugin.  In some implementations
this is used to modify the notfications/serialize data.  The
implementations will want to test their serializers and
the easiest way to do this is via the fake_notifier.
This change allows fake_notifier to act more like
notifier with serializer being a pass in as an argument.

The serializer is passed to subnotifiers created via
the prepare method.

Change-Id: I03ef9ed92366961d4e296381d149c54d7da97f70

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