Bump version 0.5.2

Change-Id: I4526377eac294925cac339b16ea143442d6302f0
Reviewed-on: http://review.couchbase.org/24824
Reviewed-by: Sergey Avseyev <sergey.avseyev@gmail.com>
Tested-by: Sergey Avseyev <sergey.avseyev@gmail.com>