modulecmd: initialise Dir2OverlayMap for all available groups

till now Dir2OverlayMap was only initialise for used groups. This is
not sufficient, if a module outside the used groups is loaded via
module load group:name.

Pmodules/libpmodules.bash.in

@@ -62,9 +62,10 @@ scan_groups () {
         local    ol
         for ol in "$@"; do
 		local mod_root="${OverlayInfo[${ol}:mod_root]}"
-	        local moduledir
-	        for moduledir in ${mod_root}/*/${PMODULES_MODULEFILES_DIR}; do
-		        compute_group_depth "${moduledir}"
+	        local dir
+	        for dir in ${mod_root}/*/${PMODULES_MODULEFILES_DIR}; do
+		        compute_group_depth "${dir}"
+			Dir2OverlayMap[${dir}]="${ol}"
 	        done
         done
 }

Pmodules/modulecmd.bash.in

@@ -608,13 +608,13 @@ subcommand_load() {
                                                  "${CMD}" "${subcommand}" \
                                                  "illegal group name" \
                                                  "${group}"
-				MODULEPATH=""
+				#MODULEPATH=""
 				modulepath=()
-				group+="${PMODULES_MODULEFILES_DIR}"
+				group+="/${PMODULES_MODULEFILES_DIR}"
                                 for overlay in "${UsedOverlays[@]}"; do
 					local mod_root="${OverlayInfo[${overlay}:mod_root]}"
-                                        MODULEPATH="${mod_root}/${group}/:${MODULEPATH}"
-				        modulepath=( "${mod_root}/${group}/" "${modulepath[@]}" )
+                                        #MODULEPATH="${mod_root}/${group}:${MODULEPATH}"
+				        modulepath=( "${mod_root}/${group}" "${modulepath[@]}" )
                                 done
 			fi
 			if [[ -n ${rel_stage} ]]; then