Fix logical error in legacy config expression

We should check for an undefined and not just for a logical true or
false.

Example: When `usecdn` was set to false it was impossible to overwrite
the new config value because the if statement becomes false.

Thanks @davidmehren for pointing me to this issue.

Signed-off-by: Sheogorath <sheogorath@shivering-isles.com>

0 files changed, 0 insertions, 0 deletions