Metrics filter may submit metrics with regular expressions in their name

[wilkinsona]

If a request mapping variable is constrained with a regular expression, metrics filter includes the regular expression in the name of the metric. For example, a request that's handled by @RequestMapping("/foo/{bar:[a-z]+}") and has a 200 OK response will result in a metric named status.200.foo.bar:[a-z]+ being submitted.

This behaviour isn't documented anywhere and doesn't appear to be covered by the tests. I suspect that it is not intentional, particularly as we replace ** with -star-star- and * with -star-. This replacement means that someVariable:[a-z]* becomes some-variable:[A-Z]-star-