Use single quotes to allow values containing spaces and commas

Test with puppet parser validate and puppet-lint.
http://docs.puppetlabs.com/guides/style_guide.html

An "invalid tag" error was thrown is the value was something like "[10.1.2.3]".
The trick was to surround the value with single quotes.
Thanks gmambro for the bug report.

find . -type f -exec perl -pi -e 's/postfix-ng/postfix/' {} \;