Introduce utsname namespaces. Instead of a single system_utsname
containing hostname domainname etc, a process can request it's
copy of the uts info to be cloned. The data will be copied from
it's original, but any further changes will not be seen by processes
which are not it's children, and vice versa.
This is useful, for instance, for vserver/openvz, which can now clone
a new uts namespace for each new virtual server.
Changes since last submission:
As per Eric's suggestion, switched several uses of init_utsname
to (per-process namespace) utsname().
Implemented UTS namespace cloning through clone and unshare.
-serge