[Pkg-samba-maint] Bug#672497: full support for usershares (public shares)

[email.bug at arcor.de]

Package: samba

The default samba configuration in debian allows regular users to 
create shares with "net usershare" and its (filemanager) GUI frontends.
(as of #443230)

However, users are not able to make their shares public.
(e.g. nautilus-shares option is grayed out)

To enabling this funtionality, one still needs to add the following settings
manually:
usershare allow guests = yes
map to guest = bad user

As the system shares defined in the default config have explicit 
"guest ok = no" lines, it looks to me that it should not produce a problem to 
add these settings to the default global section, or define them at compile time.

Nevertheless, to limit the sharing to files owned by the creator of a share, 
the following may be a suitable default:
usershare owner only = yes

Please, adjust the defaults for full support for usershares.