[ios] fix bug, iOS 10 crash if not set camera usage description
[ios] fix bug, iOS 10 crash if not set camera usage description

cxfeng1/incubator-weex,miomin/incubator-weex,lvscar/weex,weexteam/incubator-weex,acton393/incubator-weex,boboning/weex,HomHomLin/weex,alibaba/weex,misakuo/incubator-weex,misakuo/incubator-weex,KalicyZhou/incubator-weex,KalicyZhou/incubator-weex,acton393/incubator-weex,erha19/incubator-weex,dianwodaMobile/DWeex,Hanks10100/weex,Tancy/weex,miomin/incubator-weex,Neeeo/incubator-weex,yuguitao/incubator-weex,alibaba/weex,bigconvience/weex,boboning/weex,KalicyZhou/incubator-weex,MrRaindrop/incubator-weex,Hanks10100/weex,zzyhappyzzy/weex,boboning/weex,acton393/incubator-weex,miomin/incubator-weex,misakuo/incubator-weex,namedlock/weex,KalicyZhou/incubator-weex,acton393/incubator-weex,zhangquan/weex,MrRaindrop/weex,Tancy/weex,kfeagle/weex,HomHomLin/weex,dianwodaMobile/DWeex,miomin/incubator-weex,Hanks10100/incubator-weex,leoward/incubator-weex,leoward/incubator-weex,Hanks10100/incubator-weex,cxfeng1/incubator-weex,zhangquan/weex,namedlock/weex,LeeJay0226/weex,dianwodaMobile/DWeex,dianwodaMobile/DWeex,kfeagle/weex,HomHomLin/weex,yuguitao/incubator-weex,acton393/incubator-weex,misakuo/incubator-weex,MrRaindrop/weex,acton393/weex,erha19/incubator-weex,LeeJay0226/weex,kfeagle/weex,zzyhappyzzy/weex,acton393/weex,MrRaindrop/weex,xiayun200825/weex,xiayun200825/weex,boboning/weex,Neeeo/incubator-weex,Hanks10100/incubator-weex,bigconvience/weex,erha19/incubator-weex,Tancy/weex,cxfeng1/weex,acton393/incubator-weex,acton393/weex,MrRaindrop/incubator-weex,yuguitao/incubator-weex,alibaba/weex,Hanks10100/weex,xiayun200825/weex,namedlock/weex,cxfeng1/weex,weexteam/incubator-weex,kfeagle/weex,xiayun200825/weex,cxfeng1/weex,alibaba/weex,namedlock/weex,xiayun200825/weex,leoward/incubator-weex,MrRaindrop/weex,erha19/incubator-weex,KalicyZhou/incubator-weex,xiayun200825/weex,lvscar/weex,kfeagle/weex,zhangquan/weex,Tancy/weex,MrRaindrop/incubator-weex,boboning/weex,miomin/incubator-weex,acton393/weex,kfeagle/weex,acton393/weex,cxfeng1/incubator-weex,zhangquan/weex,HomHomLin/weex,zhangquan/weex,weexteam/incubator-weex,weexteam/incubator-weex,alibaba/weex,zzyhappyzzy/weex,MrRaindrop/weex,Hanks10100/incubator-weex,bigconvience/weex,leoward/incubator-weex,Hanks10100/weex,namedlock/weex,Neeeo/incubator-weex,zzyhappyzzy/weex,cxfeng1/incubator-weex,LeeJay0226/weex,Hanks10100/incubator-weex,erha19/incubator-weex,cxfeng1/incubator-weex,KalicyZhou/incubator-weex,HomHomLin/weex,boboning/weex,Neeeo/incubator-weex,Hanks10100/weex,miomin/incubator-weex,Hanks10100/incubator-weex,zzyhappyzzy/weex,dianwodaMobile/DWeex,LeeJay0226/weex,yuguitao/incubator-weex,LeeJay0226/weex,Tancy/weex,alibaba/weex,Hanks10100/weex,weexteam/incubator-weex,cxfeng1/weex,lvscar/weex,bigconvience/weex,HomHomLin/weex,erha19/incubator-weex,lvscar/weex,miomin/incubator-weex,cxfeng1/incubator-weex,acton393/incubator-weex,bigconvience/weex,Hanks10100/incubator-weex,MrRaindrop/incubator-weex,leoward/incubator-weex,weexteam/incubator-weex,cxfeng1/weex,Neeeo/incubator-weex,LeeJay0226/weex,MrRaindrop/incubator-weex,zhangquan/weex,lvscar/weex,Hanks10100/incubator-weex,misakuo/incubator-weex,leoward/incubator-weex,Neeeo/incubator-weex,namedlock/weex,lvscar/weex,yuguitao/incubator-weex,MrRaindrop/incubator-weex,dianwodaMobile/DWeex,misakuo/incubator-weex,Tancy/weex,acton393/weex,MrRaindrop/weex,acton393/incubator-weex,zzyhappyzzy/weex,bigconvience/weex,cxfeng1/weex,miomin/incubator-weex,erha19/incubator-weex,erha19/incubator-weex,alibaba/weex,yuguitao/incubator-weex