Require sudo password for mounting

Require password when you insert an USB stck or USB drive. Modify "ResultActive=yes" to "ResultActive=auth_admin_keep"

sudo gedit /var/lib/polkit-1/localauthority/10-vendor.d/com.ubuntu.desktop.pkla

...
[Mounting, checking, etc. of internal drives]
...
ResultActive=auth_admin_keep
...