CCBC-286: uv: use same CRT for free/malloc

Change-Id: If394801246ac5ac40575e48760dee5e50c86a7ba
Reviewed-on: http://review.couchbase.org/29751
Reviewed-by: Sergey Avseyev <sergey.avseyev@gmail.com>
Tested-by: Sergey Avseyev <sergey.avseyev@gmail.com>