Update Makefile

Author: vmcj

doc/manual/Makefile

@@ -55,7 +55,7 @@ clean-l:
 maintainer-clean-l:
 	rm -rf build conf_ref.rst
 
-distclean-l:
+distclean:
 	-rm -f $(SUBST_CONFIGS) html team
 
 conf_ref.rst: gen_conf_ref.py