Description:
------------
Using date_parse_from_format() with a Unix Timestamp yields no error, but does not yields valid results as well. It sets the date to 1970-1-1, instead of the correct date.

Test script:
---------------
$ php -a
Interactive mode enabled

php > $unix = date('U');
php > echo $unix;
1454336317
php > echo date('Y-m-d H:i:s', $unix);
2016-02-01 12:18:37
php > print_r(date_parse_from_format('U', $unix));
Array
(
    [year] => 1970
    [month] => 1
    [day] => 1
    [hour] => 0
    [minute] => 0
    [second] => 0
    [fraction] => 0
    [warning_count] => 0
    [warnings] => Array
        (
        )

    [error_count] => 0
    [errors] => Array
        (
        )

    [is_localtime] => 1
    [zone_type] => 1
    [zone] => 0
    [is_dst] => 
    [relative] => Array
        (
            [year] => 0
            [month] => 0
            [day] => 0
            [hour] => 0
            [minute] => 0
            [second] => 1454336317
        )

)

Expected result:
----------------
It should fill in the array with "2016-02-01 12:18:37" info.

Actual result:
--------------
The array is filled with "1970-01-01", without error messages.