Improve binary value handling in queries (Python 3)

[vtermanis]

To write raw binary values to e.g. a BINARY or BLOB column, one has to currently e.g. produce a hexadecimal representation to make sure MySQL always (and not just when the binary data is e.g. ASCII) interprets the input correctly:

raw_data = b'somebinarygoeshere'
cursor.exectute('INSERT INTO somewhere VALUES (UNHEX(%s))', (binascii.b2a_hex(raw_data),)

With the proposed change (only applicable to Python 3):

cursor.exectute('INSERT INTO somewhere VALUES (%s)', (raw_data,))

This is done by prepending the _binary prefix, see e.g. here and here.

For Python 2, bytearray could be handled in a similar fashion but I wasn't sure how to best implement this in the C extension given it only deals with bytes and not bytearray currently, unlike the pure-Python version (where one could simply always prepend _binary if buf is bytearray (in conversion.py).

[mysql-oca-bot]

Hi, thank you for your contribution. Please confirm this code is submitted under the terms of the OCA (Oracle's Contribution Agreement) you have previously signed by cutting and pasting the following text as a comment:
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Thanks

[vtermanis]

I confirm the code being submitted is offered under the terms of the OCA, and that I am authorized to contribute it.

[mysql-oca-bot]

Hi, thank you for your contribution. Your code has been assigned to an internal queue. Please follow
bug http://bugs.mysql.com/bug.php?id=82517 for updates.
Thanks