Fixed TLS selected_version parsing and debugging (#621)

Fixed TLS selected_version parsing and debugging (#621)

The description of the expected input was given to the wrong parsing
function. This typo may have affected parsing because it told the TLS
version tokenizer that more data may be expected for the already fully
extracted extension. I believe that the lie could affect error
diagnostic when parsing malformed input, but had no effect on handling
well-formed TLS handshakes (other than less-specific debugging).

Detected by Coverity. CID 1462621: Incorrect expression (NO_EFFECT)

Broken by master commit cd29a42.