redis-benchmark: Remove unused buffer
redis-benchmark: Remove unused buffer

This just deletes old code that didn't get removed when
logic changed.  We were setting offsets that never
got read anywhere.

Since clients are now just cloned, we don't need to track
per-client buffer offsets anywhere because they are all
the same from the original client.

fanxu/redis,Jonavin/redis,erwin00776/redis-2.8-optimize,nandhanurrevanth/redis,alpha8/redis,ideaar/redis,jacklee0810/redis,jacklee0810/redis,jaambee/redis,damy/redis,laurencee/redis,hanmichael/redis,adamweixuan/redis,jacklee0810/redis,hanmichael/redis,fanxu/redis,ScottKaiGu/redis,shanegxxiao/redis,Cybermaxs/redis,StartTheShift/redis-shift,janeasystems/redis,kolonse/redis,hanmichael/redis,shanegxxiao/redis,kts12345/redis,janeasystems/redis,erwin00776/redis-2.8-optimize,fanxu/redis,liqiang199105/redis,jacklee0810/redis,damy/redis,damy/redis,hanmichael/redis,miminus/redis,jqk6/redis,upsoft/redis,quangnguyen90/redis,enginekit/redis,adamweixuan/redis,miminus/redis,liqiang199105/redis,jqk6/redis,nandhanurrevanth/redis,jqk6/redis,miminus/redis,Cybermaxs/redis,kolonse/redis,laurencee/redis,shanegxxiao/redis,jaambee/redis,jacklee0810/redis,erwin00776/redis-2.8-optimize,Cybermaxs/redis,jaambee/redis,ScottKaiGu/redis,adamweixuan/redis,quangnguyen90/redis,janeasystems/redis,kolonse/redis,ideaar/redis,kolonse/redis,Jonavin/redis,LittlePeng/redis,StartTheShift/redis-shift,damy/redis,laurencee/redis,ScottKaiGu/redis,laurencee/redis,kolonse/redis,alpha8/redis,Jonavin/redis,upsoft/redis,upsoft/redis,sidsen/redis,LittlePeng/redis,liqiang199105/redis,miminus/redis,kts12345/redis,quangnguyen90/redis,quangnguyen90/redis,liqiang199105/redis,ScottKaiGu/redis,kts12345/redis,upsoft/redis,adamweixuan/redis,nandhanurrevanth/redis,Cybermaxs/redis,janeasystems/redis,janeasystems/redis,miminus/redis,ideaar/redis,Cybermaxs/redis,hanmichael/redis,jaambee/redis,laurencee/redis,sidsen/redis,upsoft/redis,alpha8/redis,alpha8/redis,kts12345/redis,Jonavin/redis,sidsen/redis,ScottKaiGu/redis,liqiang199105/redis,sidsen/redis,nandhanurrevanth/redis,fanxu/redis,enginekit/redis,ideaar/redis,Jonavin/redis,adamweixuan/redis,enginekit/redis,kts12345/redis,jaambee/redis,alpha8/redis,shanegxxiao/redis,nandhanurrevanth/redis,jqk6/redis,enginekit/redis,sidsen/redis,jqk6/redis,StartTheShift/redis-shift,sidsen/redis,ideaar/redis,enginekit/redis,quangnguyen90/redis,damy/redis,shanegxxiao/redis,erwin00776/redis-2.8-optimize,LittlePeng/redis