LUN-2235 Cleaned the variable names before saving.
LUN-2235 Cleaned the variable names before saving.

Valid characters for django template variables are [a-zA-Z0-9_].
Snippets that have invalid variables cannot use those variables, but creating a migration that would change them can break the snippet templates in subtle ways.

pbs/django-cms-smartsnippets,pbs/django-cms-smartsnippets,pbs/django-cms-smartsnippets,pbs/django-cms-smartsnippets