When a account is created the user name can be adjusted silently due to
some technical restrictions, like first letter capitalized or double
Please add a warning, so the user get a hint, that he choose a user name,
which is not usable as entered.
See gerrit 104926 for a discussion about this.
See http://lists.wikimedia.org/pipermail/design/2014-January/001320.html for a discussion about this.
The patch set adds a warning after the submit of the form, which needs retype of the password and resubmit, which is not the best way to do this.