Save LOCALVIMRC_ANSWERS when localvimrc_persistent >= 1

There are two options for persisting: 1 and 2.  So we need to check for
localvimrc_persistent >= 1.  Without this, when a user sets
localvimrc_persistent = 2, it actually never persists the selection.
Merge pull request #6 from jszakmeister/fix-persistence

Save LOCALVIMRC_ANSWERS when localvimrc_persistent >= 1