added config qiniu_private_url_expires_in
added config qiniu_private_url_expires_in

huobazi/carrierwave-qiniu,lazing/carrierwave-qiniu,CocaColaCat/carrierwave-qiniu,huobazi/carrierwave-qiniu,anehing/carrierwave-qiniu,weizhiwu/carrierwave-qiniu