[EH/GI] [71317016] Lock riak-client to latest possible version

Version 1.4.4 is compatible with riak-server 1.3.1 and doesn't require
code changes in seo_fusion (or other riak dependent services)
Merge pull request #1 from primedia/eh-gi-71317016-upgrade-riak-client

[EH/GI] [71317016] Lock riak-client to latest possible version