Tighten up parse_buf method
Tighten up parse_buf method

Might as well make the newly introduced method as simple and clear as
possible.

Signed-off-by: mulhern <7b51bcf507bcd7afb72bf8663752c0ddbeb517f6@redhat.com>

stratis-storage/stratisd,stratis-storage/stratisd,stratis-storage/stratisd