modulecmd: bugfix in save_env()

Unsetting 'UsedGroups' the way we did doesn't work, revert this change

Pmodules/modulecmd.bash.in

@@ -112,7 +112,6 @@ save_env() {
 	local s=$(typeset -p ${vars[@]})
 	declare -g PMODULES_ENV=$( "${base64}" --wrap=0 <<< "$s" )
 	export_env 'PMODULES_ENV'
-	unset UsedGroups
 }
 
 trap 'save_env ${g_env_must_be_saved}' EXIT