Fix None being passed into as_int().
Fix None being passed into as_int().

Currently when a create is received and the size is of NoneType
a stack trace is dumped because of the TypeError. This will
correct it so the functionality won't change, but the TypeError
is will be caught now.

Change-Id: Ic83dd182e0083c887af8f6209a23af38bfff2be7

tlakshman26/cinder-new-branch,redhat-openstack/cinder,takeshineshiro/cinder,tlakshman26/cinder-bug-fix-volume-conversion-full,Datera/cinder,sasukeh/cinder,Nexenta/cinder,NeCTAR-RC/cinder,apporc/cinder,hguemar/cinder,duhzecca/cinder,eharney/cinder,rakeshmi/cinder,ge0rgi/cinder,openstack/cinder,maelnor/cinder,nikesh-mahalka/cinder,abusse/cinder,winndows/cinder,Akrog/cinder,bswartz/cinder,alex8866/cinder,nikesh-mahalka/cinder,eharney/cinder,JioCloud/cinder,ntt-sic/cinder,apporc/cinder,inkerra/cinder,Thingee/cinder,citrix-openstack-build/cinder,mahak/cinder,julianwang/cinder,scality/cinder,Hybrid-Cloud/cinder,tlakshman26/cinder-https-changes,spring-week-topos/cinder-week,hguemar/cinder,openstack/cinder,CloudServer/cinder,j-griffith/cinder,redhat-openstack/cinder,JioCloud/cinder,dims/cinder,Thingee/cinder,julianwang/cinder,NeCTAR-RC/cinder,cloudbase/cinder,scality/cinder,phenoxim/cinder,sasukeh/cinder,Accelerite/cinder,tlakshman26/cinder-https-changes,Hybrid-Cloud/cinder,maelnor/cinder,potsmaster/cinder,blueboxgroup/cinder,dims/cinder,leilihh/cinder,citrix-openstack-build/cinder,cloudbau/cinder,manojhirway/ExistingImagesOnNFS,manojhirway/ExistingImagesOnNFS,blueboxgroup/cinder,NetApp/cinder,bswartz/cinder,phenoxim/cinder,github-borat/cinder,ntt-sic/cinder,cloudbase/cinder,citrix-openstack-build/cinder,petrutlucian94/cinder,Datera/cinder,nexusriot/cinder,cloudbau/cinder,saeki-masaki/cinder,NetApp/cinder,potsmaster/cinder,spring-week-topos/cinder-week,Accelerite/cinder,Paul-Ezell/cinder-1,rickerc/cinder_audit,tlakshman26/cinder-bug-fix-volume-conversion-full,petrutlucian94/cinder,duhzecca/cinder,leilihh/cinder,Thingee/cinder,github-borat/cinder,mahak/cinder,Paul-Ezell/cinder-1,alex8866/cinder,Nexenta/cinder,Akrog/cinder,CloudServer/cinder,rickerc/cinder_audit,winndows/cinder,scottdangelo/RemoveVolumeMangerLocks,j-griffith/cinder,inkerra/cinder,scottdangelo/RemoveVolumeMangerLocks,tlakshman26/cinder-new-branch,takeshineshiro/cinder,abusse/cinder,saeki-masaki/cinder,nexusriot/cinder,rakeshmi/cinder