Fix uniqid php-bug under windows

This is not a bug of flux but php under windows.

My backend layout had more that one `grid.row` and only in 1 of 10 requests i got all of them rendered as expected - sometimes with "no edit access", sometimes the area was simply blank.

It turned out that there is a known bug in php on windows where `uniqid()` is NOT unique if calling it  fast enough multiple times. http://samjlevy.com/php-uniqid-not-unique-on-iis-7-5/

The function is used in `RowViewHelper:53` so the grid rows often/sometimes get the same name.

I simply added the `more_entropy` parameter.