A solução é instalar o módulo correspondente do Python 3:
sudo apt-get install python3-mysql.connector
Corrige o erro import mysql.connector
:
$ python3
Python 3.5.2 (default, Nov 23 2017, 16:37:01)
[GCC 5.4.0 20160609] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import mysql.connector
>>>
E semelhante para o Python 2:
sudo apt-get install python-mysql.connector
$ python2
Python 2.7.12 (default, Dec 4 2017, 14:50:18)
[GCC 5.4.0 20160609] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import mysql.connector
>>>