Fixed to pass with edge version of Underscore
Fixed to pass with edge version of Underscore

Due to changes in https://github.com/documentcloud/underscore/commit/0ab5bdccd41e55fb02331ec7d2d0053e0bdac9e3 need to fix Backbone.Model test. It would be helpful because some people may use Backbone's unit tests in their Backbone-related projects (plugins for example).
vin100bk/backbone,jashkenas/backbone,Sachin-Ganesh/backbone,linalu1/backbone,trizko/backbone,neocotic/hipbone,rjz/boneless,youprofit/backbone,GerHobbelt/backbone,wangcan2014/backbone,jordansexton/backboner,zgl2007dj/backbone,ohbarye/backbone,aihua/backbone,alekskorolev/lightbones,cgvarela/backbone,7213/backbone,jstrimpel/backbone,gougouGet/backbone,dcheepurupalli/backbone,moccen/backbone,nikolas/backbone,Diwahars/backbone,wangdahoo/backbone,Krasnyanskiy/backbone,fanhc019/backbone,gdi2290/backbone,moimikey/backbone,tibic/backbone,jungjung917/backbone,closeio/backbone,zhangwei001/backbone,elancom/backbone,IsoldaJS/isolda-models,ThisIsManta/Backbone,tzkKrbys/backbone,howtolearntocode/backbone,yawenl/backbone,Akkuma/backbone,jstrimpel/backbone,dak/backbone,zgl2007dj/backbone,Khan/backbone,rashmisajjan/backbone,sumyfly/backbone,ywenjinlin/backbone,Aplopio/backbone,tadwhitaker/backbone,honger05/backbone,mrblueblue/backbone,liudianpeng/backbone,wangdahoo/backbone,guigrpa/backbone,alekskorolev/lightbones,tzkKrbys/backbone,megawac/backbone,wushuyi/backbone,jewsroch/backbone,timebackzhou/backbone,platinumazure/backbone,paulfalgout/backbone,antoniogarrote/backbone,Niades/backbone,ThiagoGarciaAlves/backbone,tibic/backbone,ntgn81/backbone,JesseQin/backbone,zhangdimelody/backbone,GerHobbelt/backbone,elma-cao/backbone,webcoding/backbone,dcheepurupalli/backbone,ohbarye/backbone,mpapp/backbone,FishbaitHarry/backbone,udhayam/backbone,elma-cao/backbone,premkumargithub/backbone,7213/backbone,sumyfly/backbone,sitexa/backbone,wakanpaladin/mybackbone,leimd/backbone,Bug2014/backbone,zhangdimelody/backbone,linalu1/backbone,trizko/backbone,huanglp47/backbone,LovelyL25/backbone.js,wangcan2014/backbone,akre54/backbone,jashkenas/backbone,DannyDelott/backbone,nikolas/backbone,yuhualingfeng/backbone,craigmichaelmartin/backbone,hugohua/backbone,mrblueblue/backbone,honger05/backbone,batigoal1980/backbone_example,sunday-star/backbone,webapp/library,premkumargithub/backbone,lujocom/backbone,Khan/backbone,leimd/backbone,vincent1988/backbone,getshuvo/backbone,componentizr/backbone,ebsco/backbone,yuhualingfeng/backbone,Niades/backbone,ridixcr/backbone,jmeas/backbone,ppker/backbone,elancom/backbone,feychenie/backbone,sunday-star/backbone,GrimDerp/backbone,webcoding/backbone,virtru-components/backbone,liudianpeng/backbone,streamablevideo/backbone,cailong1028/backbone,ppker/backbone,tgriesser/backbone,gougouGet/backbone,au-phiware/backbone,yawenl/backbone,anhtholee/backbone,heroazure/backbone,jridgewell/backbone,vincent1988/backbone,dak/backbone,ThisIsManta/Backbone,moimikey/backbone,youprofit/backbone,vin100bk/backbone,luffy94608/backbone,wakanpaladin/mybackbone,webapp/library,heroazure/backbone,lastjune/backbone,feychenie/backbone,craigmichaelmartin/backbone,kuychaco/backbone,zhoufan879/backbone,zhangwei001/backbone,huanglp47/backbone,jewsroch/backbone,Flip120/backbone,nvoron23/backbone,ereddate/backbone,wjb12/backbone,gmaclennan/backbone,rashmisajjan/backbone,GrimDerp/backbone,gmaclennan/backbone,getshuvo/backbone,timebackzhou/backbone,ridixcr/backbone,jasoncbautista/backboneX,chyeh727/backbone,kuychaco/backbone,mmolinastudio/backbone,Sachin-Ganesh/backbone,braddunbar/backbone,au-phiware/backbone,amdjs/backbone,streamablevideo/backbone,gitterHQ/backbone,luffy94608/backbone,lastjune/backbone,wushuyi/backbone,akre54/backbone,moccen/backbone,embarknow/backbone,sueyeh/backbone,darrrk/backbone,platinumazure/backbone,sitexa/backbone,sueyeh/backbone,jungjung917/backbone,Khan/backbone,wjb12/backbone,nvoron23/backbone,DannyDelott/backbone,guahanweb/backbone,wxmfront/backbone,batigoal1980/backbone_example,amitpatange88/backbonejs,aihua/backbone,cgvarela/backbone,zdespolit/backbone,npmcomponent/jashkenas-backbone,chyeh727/backbone,mmolinastudio/backbone,braddunbar/backbone,Connectlegendary/backbone,IsoldaJS/isolda-pubsub,cailong1028/backbone,neocotic/hipbone,ebsco/backbone,tadwhitaker/backbone,embarknow/backbone,Connectlegendary/backbone,guahanweb/backbone,wxmfront/backbone,Bug2014/backbone,LovelyL25/backbone.js,ThiagoGarciaAlves/backbone,fanhc019/backbone,FormidableLabs/backbone,jridgewell/backbone,ywenjinlin/backbone,Aplopio/backbone,zhoufan879/backbone,lujocom/backbone,Krasnyanskiy/backbone,pandoraui/backbone,amitpatange88/backbonejs,ereddate/backbone,closeio/backbone,ntgn81/backbone,FishbaitHarry/backbone,paulfalgout/backbone,Diwahars/backbone,oss-practice/backbone,darrrk/backbone,Flip120/backbone,zdespolit/backbone,udhayam/backbone,pandoraui/backbone,JesseQin/backbone,howtolearntocode/backbone,Aplopio/backbone,anhtholee/backbone,jmeas/backbone