Fixes #6514: advanced application SignupForm::signup() should not return User model if saving failed
Fixes #6514: advanced application SignupForm::signup() should not return User model if saving failed


deesoft/yii2-app-single,krissss/YunDou-advanced,jhliliang/YunDou-advanced,AnTAVR/yii2-app-advanced-ru,marciocamello/yii2-app-advanced,jacmoe/yii2-app-advanced-zurbified,AnTAVR/yii2-app-advanced-ru,MatheusBarem/yii2-app-advanced,cophiel/YII2-Learning,yiisoft/yii2-app-advanced,deerawan/yii2-app-advanced,fredyns/yii2-boilerplate,fuhongliang/yii2-app-advanced,fuhongliang/YunDou-advanced,Silver90/yii2-app-advanced,fuhongliang/YunDou-advanced,fredyns/yii2-boilerplate,GAMITG/yii2-app-angular,subdee/myportugal,RyanTech/YunDou-advanced,AnTAVR/yii2-app-advanced-ru,tigokr/id20_test_0,Somefive/Athena,tibrus/yii2-app-advanced,dmitry-kulikov/yii2-app-advanced,Takune/yii2-app-advanced,dixonsatit/yii2-dixon-starter,wfcreations/yii2-app-api,diandianxiyu/yii2-app-api,dixonsatit/yii2-dixon-starter,urmaul/yii2-app-advanced-mongodb,tigokr/id20_test_0,Somefive/Athena,OneServices/OneCMS,farindra/yii2-application,yiijan/yii2-app-advanced,fredyns/yii2-boilerplate,smartnisarg23/yii2-app-advanced,dmitry-kulikov/yii2-app-advanced,weilanhzuan/yii2-app-api,cophiel/YII2-Learning,deesoft/yii2-application,erycamel/yii2-app-advanced,deesoft/yii2-app-single,jhliliang/YunDou-advanced,jacmoe/yii2-app-advanced-zurbified,jgege/MonApp,jgege/MonApp,vitezmiklos/test,fuhongliang/YunDou-advanced,whq78164/yii2-app-advanced,subdee/myportugal,nikbas/yii2-app-advanced,farindra/yii2-application,firstval/yii2-app-advanced,erycamel/yii2-app-advanced,yiijan/yii2-app-advanced,nikbas/yii2-app-advanced,wartron/yii2-app-advanced,yiisoft/yii2-app-advanced,jhliliang/YunDou-advanced,offsite-solutions/framework,githubjeka/yii2-app-advanced,mobilejazz/yii2-mj-cms-example,mobilejazz/yii2-mj-cms-example,krissss/YunDou-advanced,RyanTech/YunDou-advanced,deesoft/yii2-application,githubjeka/yii2-app-advanced,pana1990/yii2-app-advanced,lymos/yii2-app-advanced,krissss/YunDou-advanced,hiqsol/yii2-app-advanced