Return the first random string if RandomCharField is not unique (#752).
Return the first random string if RandomCharField is not unique (#752).

`random_chars` is a generator so we eneed to take the first value from it if we
do not care about uniqueness.

kevgathuku/django-extensions,linuxmaniac/django-extensions,linuxmaniac/django-extensions,django-extensions/django-extensions,haakenlid/django-extensions,jpadilla/django-extensions,haakenlid/django-extensions,jpadilla/django-extensions,linuxmaniac/django-extensions,django-extensions/django-extensions,dpetzold/django-extensions,kevgathuku/django-extensions,kevgathuku/django-extensions,django-extensions/django-extensions,dpetzold/django-extensions,haakenlid/django-extensions,jpadilla/django-extensions,dpetzold/django-extensions