Trying to set a name that is already in use will throw an exception (and
set a different, generated name); if there is actually no name in the
file then there's no point trying to set anything.
(regression from b69d152cfa1da868ba960345d72ba78f9f8e1b35)
Change-Id: Ie54d4a830cc23e2853a6efeb81f77dcc788192ea