Misleading error related to attachment size

Issue Summary

You can control the size limit of attachments on https://<YOUR_SITE>.atlassian.net/secure/admin/ViewAttachmentSettings.jspa.

That will prevent users from uploading attachments whose size is greater than the one specified on that page. But currently the message displayed when users try to do so is completely misleading, giving the idea that the upload should have worked:

Steps to Reproduce

• Configure the attachment size limit to a value
• Try uploading an attachment with a greater value to an issue

Expected Results

A message stating that the attachment is greater than the limit allowed will be displayed.

Actual Results

A message asking the user to try again will be displayed:

Reload the issue then try adding it again.

Workaround

In case you run into that message, check your instance's attachments settings on https://<YOUR_SITE>.atlassian.net/secure/admin/ViewAttachmentSettings.jspa