Initialize winsock (ep-engine tests need it)

Change-Id: Icefa4bd90681ddff5d18de8471581baa768aa656
Reviewed-on: http://review.couchbase.org/31618
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>