fixed android 6.0+ fetch HEAD network error bugs

[oneroundseven]

facebook/react-native#18440

[coveralls]

Coverage decreased (-1.4%) to 92.114% when pulling daf0734 on oneroundseven:master into a2880e9 on billmalarky:master.

[billmalarky]

Looks like there are linting errors. To problem I can quickly solve those with my own commit.

The larger issue here, is this is not a solution to the bug.

A patch will need to be applied in this function: https://github.com/billmalarky/react-native-image-cache-hoc/blob/master/lib/FileSystem.js#L186-L227

For what it's worth, you will not run into this issue so long as the images you are using for CacheableImage have an extension in the url like .jpg/.png.gif etc.

[oneroundseven]

but some server image url not has the .jpg/.png ...
and the server return fetch is correct, but fetch not correct call back with the issue error