use hashing function exposed by browserify

[voidlock]

As of version 3.31.5 browserify uses relative paths to compute the file
hash. This means the karma-browserify bundle is incorrectly
hashing file ids to be required by the tests.

The hashing function is now available directly on the browserify bundle
instance (see browserify/browserify@9499ffb). This commit fixes the
above mentioned issue by delegating the file id hashing to this exposed
function.

At the moment though, that hashing function is prefixed with an _
possibly indicating that it's intended for private internal usage. So
any changes to this methods name or placement will break this code. In
that case though, the break will be much easier to detect than the
errors caused previously.

[klipstein]

@voidlock just stumbled upon this issue too and it was version 3.30.5 (just a minor correction) and this commit browserify/browserify@7abcc7d) which breaks karma-browserify with the latest browserify version. Using your branch fixed it in my environment.

[klipstein]

@voidlock just stumbled upon this issue too and it was version 3.30.5 (just a minor correction) and this commit browserify/browserify@7abcc7d) which breaks karma-browserify with the latest browserify version. Using your branch fixed it in my environment.

[alexgorbatchev]

Thanks for the PR!

[alexgorbatchev]

Thanks for the PR!