Correct method fix_ace_over_21

After replacing the value of each Ace with 1 only add 10 if total is
less than or equal to 11. Otherwise add 0. This will give 21 if there
are multiple Aces plus total of non Ace cards.

Example

[5, 4, 11, 11] # => 31

fix_ace_over_21 will change the array with card values to

[5, 4, 1, 1, 10, 0] => 21