Raise different exception when hash value of download is wrong

[e-mny]

One thing we may want to change later is to raise a different exception when the hash fails here. It should maybe raise something specific to this and so isn't suppressed by skip_if_download_fails. Let's not worry about that in this PR yet however.

Originally posted by @ericspod in #8699 (comment)

[AlexanderSanin]

Hi @e-mny , I've submitted a PR for this: #8861. It adds a HashMismatchError(RuntimeError) exception and updates download_url and skip_if_downloading_fails accordingly. Backward compatible since it inherits from RuntimeError. Happy to adjust if needed.

[ericspod]

Hi @vikashg we had been working on #8833 for this issue, that's now merged after delays but let's look at what the other contributors had to see if we can integrate changes from them as well.