Add consistent APIs for setex and setnx on top of txredis.
Add consistent APIs for setex and setnx on top of txredis.

TouK/vumi,vishwaprakashmishra/xmatrix,harrissoerja/vumi,TouK/vumi,vishwaprakashmishra/xmatrix,harrissoerja/vumi,TouK/vumi,vishwaprakashmishra/xmatrix,harrissoerja/vumi