FIX: Fix check

[larsoner]

On latest NumPy dev I get a lot of these warnings when using h5py:

h5py/__init__.py:36: FutureWarning: Conversion of the second argument of issubdtype from `float` to `np.floating` is deprecated. In future, it will be treated as `np.float64 == np.dtype(float).type`.

This gets rid of them, but I'm not sure if the check should be more or less specific than this, but I think this is the change suggested by the warning message.

[larsoner]

... looks like this fix is already part of #926. Feel free to close if it's better to leave it to that PR.

[aragilar]

I'm merging this, and it should be backported to a 2.7.2 release (my PR is more complicated, so that should only go in a potential 2.8 release).

[larsoner]

Let me know if you need me to do anything for the 2.7.2 backport like open a separate PR

[Erotemic]

Is there any change of getting this into a release anytime soon? This warning has been appearing for months now.

[aragilar]

@Erotemic See https://groups.google.com/forum/#!topic/h5py/liapKtBCmlE, the final release should be coming out soon.