no need for DATADIR/why3/emacs

Makefile.in

@@ -297,7 +297,6 @@ endif
 	mkdir -p $(DATADIR)/why3/images
 	mkdir -p $(DATADIR)/why3/images/boomy
 	mkdir -p $(DATADIR)/why3/images/fatcow
-	mkdir -p $(DATADIR)/why3/emacs
 	mkdir -p $(DATADIR)/why3/vim
 	mkdir -p $(DATADIR)/why3/lang
 	mkdir -p $(DATADIR)/why3/theories