shadow fix

sys/apps/shadow/shadow.sysconf

@@ -3,5 +3,15 @@ if [ ! -f /var/lib/ymp/sysconf/shadow/postinstall.done ] ; then
     for app in su chage chsh expiry ; do
         chmod u+s /usr/bin/$app
     done
+    touch /etc/group
     date > /var/lib/ymp/sysconf/shadow/postinstall.done
 fi
+if ! grep "^users:" /etc/group >/dev/null ; then
+    echo "users:x:100:" >> /etc/group
+fi
+if ! grep "^wheel:" /etc/group >/dev/null ; then
+    echo "wheel:x:10:root" >> /etc/group
+fi
+if ! grep "^root:" /etc/group >/dev/null ; then
+    echo "root:x:0:root" >> /etc/group
+fi