geometric_distribution::min() returns wrong value

[bolero.murakami+cpp@…]

geometric_distribution::min() returns always 1. (boost 1.47)

I think, this is a wrong value. Should return 0.

In fact, boost::random::geometric_distribution::operator()(Engine) is sometimes returns 0.

The boost::random::geometric_distribution class has been updated to match the C++ standard.

Boost 1.46.1 : p(i) = (1-p)p^(i-1)

Boost 1.47 : p(i) = p(1-p)ⁱ

If the previous specification, then it should return 1.

However, the current specification, should return 0.

[Steven Watanabe]

(In [74168]) geometric_distribution::min should be 0. Fixes #5704.