Minor documenation bug (confusing dir and heapdir)
Minor documenation bug (confusing dir and heapdir)

See https://github.com/MSOpenTech/redis/issues/218

janeasystems/redis,jqk6/redis,damy/redis,Cybermaxs/redis,kts12345/redis,shanegxxiao/redis,janeasystems/redis,jaambee/redis,Cybermaxs/redis,janeasystems/redis,damy/redis,liqiang199105/redis,laurencee/redis,Cybermaxs/redis,quangnguyen90/redis,ideaar/redis,quangnguyen90/redis,jaambee/redis,kts12345/redis,laurencee/redis,upsoft/redis,upsoft/redis,adamweixuan/redis,enginekit/redis,jqk6/redis,ideaar/redis,jqk6/redis,enginekit/redis,miminus/redis,ScottKaiGu/redis,jaambee/redis,upsoft/redis,alpha8/redis,laurencee/redis,jaambee/redis,shanegxxiao/redis,jacklee0810/redis,hanmichael/redis,Cybermaxs/redis,adamweixuan/redis,Jonavin/redis,alpha8/redis,damy/redis,jaambee/redis,ScottKaiGu/redis,shanegxxiao/redis,laurencee/redis,Jonavin/redis,jacklee0810/redis,ScottKaiGu/redis,kts12345/redis,jacklee0810/redis,liqiang199105/redis,shanegxxiao/redis,hanmichael/redis,enginekit/redis,Jonavin/redis,damy/redis,miminus/redis,adamweixuan/redis,quangnguyen90/redis,ideaar/redis,alpha8/redis,shanegxxiao/redis,adamweixuan/redis,alpha8/redis,kolonse/redis,Jonavin/redis,kolonse/redis,damy/redis,janeasystems/redis,hanmichael/redis,ScottKaiGu/redis,Cybermaxs/redis,ScottKaiGu/redis,ideaar/redis,upsoft/redis,laurencee/redis,janeasystems/redis,liqiang199105/redis,hanmichael/redis,liqiang199105/redis,kolonse/redis,miminus/redis,enginekit/redis,quangnguyen90/redis,enginekit/redis,miminus/redis,kolonse/redis,miminus/redis,hanmichael/redis,kolonse/redis,kts12345/redis,quangnguyen90/redis,liqiang199105/redis,jacklee0810/redis,upsoft/redis,jqk6/redis,Jonavin/redis,alpha8/redis,ideaar/redis,kts12345/redis,jacklee0810/redis,adamweixuan/redis,jqk6/redis