Remove apostrophe from random chars

A naive copy/paste of the random string can generate a syntax error because of the apostrophe. 
```
Traceback (most recent call last):
  File "manage.py", line 24, in <module>
...
  File "/opt/apps/timesketch/timesketch/settings.py", line 102
    SECRET_KEY = 'Kqg'1Z%v`_(J(cMw7?^B+6.IUGY=G>:D9kG;DZwL2-7BH5qwo'

SyntaxError: invalid syntax
```
Ok, got it.