[BrowserKit] At Cookie fromString() remove some strtolower

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | 
| License       | MIT
| Doc PR        |

I can revert the change to ternary operator if someone don't like it

I thinked in move the if ('httponly' to before if ('secure' just as a minor performance optimization, but I don't have  any data to support it