Made the filename of compiled files explicit, i.e. add a ./ prefix
whenever the filename was given alone. This caused strange behaviour
of coqtop that was compiling stuff we didn't want to just because
it was somewhere in its loadpath.

This is why FingerTree was not compiling, btw, as it had two files
equally named in two different paths.

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@16788 85f007b7-540e-0410-9357-904b9bb8a0f7