Replace type="guid" with type="new" in gnucash-xea files

Having type="guid" causes the accounts created from the file to use
the example GUID instead of generating a new one.

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@23780 57a11ea4-9604-0410-9ed3-97b8803252fd