Bug fix for wrong salt used when calculating scramble after authentication switch.

[twocode]

https://dev.mysql.com/doc/internals/en/connection-phase-packets.html#packet-Protocol::AuthSwitchRequest

The last zero byte should not be included in the salt when re-calculating the scramble responding to auth switch request.

(related issue on JIRA: https://jira.mariadb.org/browse/CONJ-394)

[rusher]

Hi twocode,

Thanks for you contribution, as explain in https://jira.mariadb.org/browse/CONJ-394, i agree that current implementation can be improve for better clarity.

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Thanks,
diego

[twocode]

@rusher Hey Diego, please verify if it's sufficient with the statement provided in the following comment above :)

Are you suggesting in JIRA that we should take this fix selectively per plugin, instead of what has been done in this PR where the last byte is trimmed under all circumstances? Since auth_pem takes them all.

[vaintroub]

I think bytes are either trimmed or not. How can protocol selectively work for some plugins and not for others, Id like to understand that

[twocode]

@vaintroub Please see the JIRA thread. auth_pem will consumes all the data.

@rusher I have seen you committed the fix. Please close this PR :) Looking forward to next release.

[rusher]

closing, since fixed differently in release 1.5.6