BZ #1173730 - add default type for new cluster network params.

https://bugzilla.redhat.com/show_bug.cgi?id=1173730

If these are not set, when using ofi installer, the correct datatype will not be
set for the new pcmk_ params (string instead of array).
Merge pull request #439 from jguiditta/BZ#1173730-add-seeds-change

BZ #1173730 - add default type for new cluster network params.