Piwik HTTP URL Validation (trailing slash)

Issue Summary

When entering a piwik HTTP url without a trailing slash, the field fails validation.
e.g. http://analytics.example.com (no trailing slash)
The error message would be:
"The validation of "http://analytics.example.compiwik.php" failed with error "php_network_getaddresses: getaddrinfo failed: Name or service not known" (HTTP code 0)."

This can be confusing, as it is very subtle. It would be helpful if the form validator would automatically add the trailing slash, or some similar solution.

This is a usability bug.
Usability Heuristics:
Error Prevention
Even better than good error messages is a careful design which prevents a problem from occurring in the first place. Either eliminate error-prone conditions or check for them and present users with a confirmation option before they commit to the action.

Help users recognize, diagnose, and recover from errors
Error messages should be expressed in plain language (no codes), precisely indicate the problem, and constructively suggest a solution.
Source: http://www.useit.com/papers/heuristic/heuristic_list.html