Adding some selectability to host creation for testing. Using find_or_create_by results in lots of saves instead of one big one at the end, which causes initial saving to be much slower. To switch between them, just modify the value of "create" at the top of Host.store.

git-svn-id: https://reductivelabs.com/svn/puppet/trunk@1936 980ebf18-57e1-0310-9a29-db15c13687c0