random.tcc (uniform_int_distribution<>::operator()): Fix to work well for arbitrary urng.max() and urng.min().

2010-06-20  Paolo Carlini  <paolo.carlini@oracle.com>
	    Kai-Uwe Bux  <bux@kubux.net>

	* include/bits/random.tcc (uniform_int_distribution<>::operator()):
	Fix to work well for arbitrary urng.max() and urng.min().

Co-Authored-By: Kai-Uwe Bux <bux@kubux.net>

From-SVN: r161054