Give the user help on checksum errors

[rolandwalker]

No description provided.

[nanoxd]

I don't agree with adding this in there. The users that we cater to would have the know-how to run through updates to fix their issue. It would be better to encourage submitting a PR with the new checksum for obscure software with a smaller user base.

[rolandwalker]

FWIW, this PR was simply my response to the exchange below on IRC. In my mind: end-users are First in importance, Cask authors are Second, Developers are Last.

Would you like this PR better if the message said "try the update and if that doesn't work, here's how to submit a Cask fix"?

2014-01-14, #homebrew-cask
14:05 David: has anyone managed to install onepassword?
14:05 David: I'm getting this:
14:05 David: ==> Downloading http://i.agilebits.com/dist/1P/mac4/1Password-4.1.3.zip
14:05 David: ######################################################################## 100.0%
14:05 David: Error: SHA1 mismatch
14:05 David: Expected: 092f804d377650aa68f1301e2bfa8cea4f5d6e74
14:05 David: Actual: d3a8db299af0ad3793658d6f9a3e2c74cea8aed6
14:07 Cottser: David: brew update
14:07 Cottser: https://github.com/phinze/homebrew-cask/commit/d12f7f7e4b08639f7220b36cfb65242f1730dbe0
14:08 David: Right, thanks.
14:08 David: bangs head.

[vitorgalvao]

Would you like this PR better if the message said "try the update and if that doesn't work, here's how to submit a Cask fix"?

I’d have no problem with that. Something like “Please run “brew update” and try again. If that does not solve the issue, please let us know — https://github.com/phinze/homebrew-cask/issues/new”.

[phinze]

This seems okay to me. Always better to be nicer to the user 🐭