fix use of deprecated API

see following puppet commit for more information:
https://github.com/puppetlabs/puppet/commit/895de3b418c294326ef2ea65002aeca4a40e27a8

I think the warnings about the following already initialized constants (line 18-20) have also the reason in this commit.. something about that every run now initialize this stuff... but sorry I do not understand enough to fix this in a reasonable time too. But this commit was a no brainer :) 
DEFAULT_TYPE = 'single'
DEFAULT_METHOD = 'value'
DEFAULT_SEP = ','