isr_admin: Fix up adduser
isr_admin: Fix up adduser

- Pass -m option to useradd to create home directory

- Use chpasswd to set the password, since passwd doesn't take --stdin
anymore

- Set the user's home directory to mode 700 to protect the keyroots

cmusatyalab/openisr,cmusatyalab/openisr,cmusatyalab/openisr,cmusatyalab/openisr,cmusatyalab/openisr