[Users] GetComponents doesn't handle repository declarations without thorns

I had the following lines in my thorn list:

# Private thorns !TARGET = $ARR !TYPE = ignore !CHECKOUT =

Note that the checkout item is empty. GetComponents reports two errors:

$ utils/Scripts/GetComponents --update --root=. manifest/einsteintoolkit.th Odd number of elements in hash assignment at utils/Scripts/GetComponents line 335. Use of uninitialized value in split at utils/Scripts/GetComponents line 441.

It should instead either report an error, or handle the case of a repository without thorns correctly.

-erik