Break out of Iter.Next if getMore failed.
Break out of Iter.Next if getMore failed.

Problem reported by Daniel Gottlieb.

tchajed/mgo,dmage/mgo,deafgoat/mgo,tobyzxj/mgo,lucasjo/mgo,deafgoat/mgo,jjz/mgo,jjz/mgo,Yottaa/mgo.v2,go-mgo/travis-test,Danzeer/mgo,Danzeer/mgo,dmage/mgo,DroiTaipei/mgo,henrylee2cn/mgo,henrylee2cn/mgo,raymondjacobson/mgo,SocialExplorerFork/mgo,raymondjacobson/mgo,SocialExplorerFork/mgo,SocialExplorerFork/mgo,tmc/mgo,go-mgo/travis-test,gabrielrussell/mgo,gabrielrussell/mgo,tchajed/mgo,gabrielrussell/mgo,raymondjacobson/mgo,tobyzxj/mgo,Yottaa/mgo.v2,velocity-toolkit/mgo,tchajed/mgo,tobyzxj/mgo,dmage/mgo,deafgoat/mgo,Yottaa/mgo.v2,DroiTaipei/mgo,mcuadros/mgo,jjz/mgo,hexadecy/mgo,tchajed/mgo,mjs/mgo,gabrielrussell/mgo,go-mgo/travis-test,mcuadros/mgo,tmc/mgo,velocity-toolkit/mgo,hexadecy/mgo,tchajed/mgo,velocity-toolkit/mgo,jackspirou/mgo,mcuadros/mgo,lucasjo/mgo,tmc/mgo,mjs/mgo,dmage/mgo,deafgoat/mgo,tmc/mgo,hexadecy/mgo,DroiTaipei/mgo,mjs/mgo,henrylee2cn/mgo,jackspirou/mgo,tobyzxj/mgo,go-mgo/travis-test,mjs/mgo,Yottaa/mgo.v2,jjz/mgo,lucasjo/mgo,mcuadros/mgo,velocity-toolkit/mgo,henrylee2cn/mgo,Danzeer/mgo,lucasjo/mgo,jackspirou/mgo,raymondjacobson/mgo,DroiTaipei/mgo,Danzeer/mgo,SocialExplorerFork/mgo,jackspirou/mgo,hexadecy/mgo