Fixing issue equal keys although there are different fields.

`FormSignature::key()` use Blowfish algorithm for signature.
In this algorithm only first 72 char will be crypt [see `Caution` in http://php.net/manual/en/function.crypt.php].
For this reason, when we use more fields (that serialize of this fields are more than 72 char), we can change the last name of fields without changing signature. (this issue mentioned in #998 & #1106)

other problems happened in other tests when i fixed above issue. So, i was forced to fix that problems in this commit.