keepalive is being ignored

As i commented here: https://github.com/loopj/android-async-http/issues/382#issuecomment-166585918
we see that connections are still getting closed with this lib ignoring the keepalive setting returned from our server.
Used Version: 1.4.9

I'am writing this here again because i believe my comment is not getting any attention.
It's still a big problem for us because we are enforcing ssl which leads us to noticable delays.

```
2015/12/08 17:58:31 [info] 15865#0: *458947 client ::ffff:41.33.xx closed keepalive connection
2015/12/08 17:58:31 [info] 15865#0: *458950 client ::ffff:41.33.xx closed keepalive connection
2015/12/08 17:58:31 [info] 15865#0: *458949 client ::ffff:41.33.xx closed keepalive connection
2015/12/08 17:58:31 [info] 15865#0: *458948 client ::ffff:41.33.xx closed keepalive connection
2015/12/08 17:58:33 [info] 15865#0: *458951 client ::ffff:41.33.xx closed keepalive connection
2015/12/08 17:58:35 [info] 15865#0: *458963 client ::ffff:41.33.xx closed keepalive connection
2015/12/08 17:58:35 [info] 15865#0: *458965 client ::ffff:41.33.xx closed keepalive connection
2015/12/08 17:58:35 [info] 15865#0: *458960 client ::ffff:41.33.xx closed keepalive connection
2015/12/08 17:58:35 [info] 15865#0: *458961 client ::ffff:41.33.xx closed keepalive connection
2015/12/08 17:58:35 [info] 15865#0: *458966 client ::ffff:41.33.xx closed keepalive connection
2015/12/08 17:58:35 [info] 15865#0: *458967 client ::ffff:41.33.xx closed keepalive connection
2015/12/08 17:58:35 [info] 15865#0: *458962 client ::ffff:41.33.xx closed keepalive connection
2015/12/08 17:58:36 [info] 15865#0: *458964 client ::ffff:41.33.xx closed keepalive connection
2015/12/08 17:58:38 [info] 15874#0: *458990 client ::ffff:41.33.xx closed keepalive connection
2015/12/08 17:58:38 [info] 15874#0: *458986 client ::ffff:41.33.xx closed keepalive connection
2015/12/08 17:58:38 [info] 15874#0: *458987 client ::ffff:41.33.xx closed keepalive connection
2015/12/08 17:58:40 [info] 15874#0: *458993 client ::ffff:41.33.xx closed keepalive connection
2015/12/08 17:58:41 [info] 15874#0: *458983 client ::ffff:41.33.xx closed keepalive connection
2015/12/08 17:58:41 [info] 15874#0: *458985 client ::ffff:41.33.xx closed keepalive connection
2015/12/08 17:58:44 [info] 15874#0: *458984 client ::ffff:41.33.xx closed keepalive connection
2015/12/08 17:58:46 [info] 15868#0: *459003 client ::ffff:41.33.xx closed keepalive connection
2015/12/08 17:58:46 [info] 15874#0: *458988 client ::ffff:41.33.xx closed keepalive connection
2015/12/08 17:58:47 [info] 15874#0: *459011 client ::ffff:41.33.xx closed keepalive connection
2015/12/08 17:58:47 [info] 15874#0: *459010 client ::ffff:41.33.xx closed keepalive connection
2015/12/08 17:58:49 [info] 15874#0: *459013 client ::ffff:41.33.xx closed keepalive connection
2015/12/08 17:58:50 [info] 15874#0: *458989 client ::ffff:41.33.xx closed keepalive connection
2015/12/08 17:58:52 [info] 15874#0: *459026 client ::ffff:41.33.xx closed keepalive connection
2015/12/08 17:58:52 [info] 15870#0: *459021 client ::ffff:41.33.xx closed keepalive connection
```