user.eclass: Prevent automated home creation in useradd

Pass '-M' to prevent useradd from automatically creating the home
directory (depending on system configuration).  We create the home
directory ourselves anyway, and we have better control over how it's
created this way.

Signed-off-by: Michał Górny <mgorny@gentoo.org>

eclass/user.eclass

@@ -209,7 +209,7 @@ enewuser() {
 		;;
 
 	*)
-		useradd -N -r "${opts[@]}" "${euser}" || die
+		useradd -M -N -r "${opts[@]}" "${euser}" || die
 		;;
 	esac