[fix] filename --> file in a few file transport examples
[fix] filename --> file in a few file transport examples

imjerrybao/nconf,olalonde/nconf,indexzero/nconf,remy/nconf,philip1986/nconf,HansHammel/nconf,Dependencies/nconf,ChristianMurphy/nconf,NickHeiner/nconf,bryce-gibson/nconf