Fixes statsd bucket name regex to accept dots

using dot characters in statsd bucket names helps to organize the data
in tools like graphite. so by sending a bucket named "site.logins" and
another named "site.logouts", in graphite you would have a tree for
"site", that contains "logins" and "logout" nodes.
Merge pull request #233 from farzadghanei/fix-statsd-bucket-name

Fixes statsd bucket name regex to accept dots