finder-compile-keywords misses some packages

[Jonas Bernoulli]

`finder-compile-keywords' keeps track of processed libraries by adding their 
base-name to a list and subsequently ignoring any file whose base-name is 
already there. However multiple files with the same base-name exist so this 
does not work properly resulting in some files being ignored when they should 
not be. E.g.:

$ find -name debug.el
./cedet/semantic/bovine/debug.el
./cedet/semantic/debug.el
./cedet/semantic/analyze/debug.el
./emacs-lisp/debug.el