Taking care of free shipping cart rule when setting "Best Price" flag

Prerequesite :
You have a Cart rule with free shipping that applies.

Before :
The "Best Price" flag can be on a non-free carrier, instead of being on the free ones.

After :
If at least one free carrier is in the list, it will has the "Best Price" flag.
Hi,

Thank you for your PR but sorry this does nto respect our current code norm. http://doc.prestashop.com/display/PS15/Coding+Standards#CodingStandards-Assignments

Regards

Regards