Fix pagination nativeArray test-unit failed

1) PaginatorTest::testArrayPaginator_t445
Failed asserting that 2 matches expected 1.

/home/vagrant/cphalcon-2.x.x/unit-tests/PaginatorTest.php:204

Bug : Divide by an integer return an integer.
Fix : Add floatval on denominator to return a float

use test-unit "PaginatorTest" to check fix