fix generated provides of files provided by more than one package

(uniqueify_properties() assumes that each property only belongs to a
single package, so our previous strategy of generating a single property
with an indirect package list wouldn't work.)

 .gitignore

 *.o

 *~

 *.repo

 razor

 test-driver

 pkgs

 set

 primary.xml.gz

 filelists.xml.gz