Target definitions beginning with curly-braced clauses aren't expanded

[Drew Stephens]

I'm using Pencil (https://github.com/fetep/pencil) with Graphite, and in the configuration I'm using it generates targets like this:

    {foo,bar}.{host*}.metric.name

It seems that Graphite chokes on the first clause being a curl-braced one; curly brace enclosed parts elsewhere work fine.

[Michael Leinartas (mleinartas)]

Committed in r691