Fixed the way pervasives.eff is looked for.
Fixed the way pervasives.eff is looked for.

It was wrong when the development version of eff was executed from a directory other than
the top-level eff directory (make test does that).

matijapretnar/eff,matijapretnar/eff,matijapretnar/eff,andrejbauer/eff,matijapretnar/eff,matijapretnar/eff