Wrong suffix check about hostname

[tsubosaka]

Riak CS don't check properly hostname ends with cs_root_host.
Riak CS only check host contains cs_root_host and don't check host ends with cs_root_host.

Here is the example request.

[vagrant@vagrant-centos65 riak_cs_1_5_2]$ s3cmd ls s3://tmp
2014-12-17 01:49        13   s3://tmp/hello.txt
[vagrant@vagrant-centos65 riak_cs_1_5_2]$ curl  -H "Host: tmp.s3.amazonaws.com" localhost:15018/hello.txt
Hello world!
[vagrant@vagrant-centos65 riak_cs_1_5_2]$ curl  -H "Host: tmp.s3.amazonaws.com.com" localhost:15018/hello.txt
Hello world!