REVERTED: APPLIED: [PATCH Quantal CVE] userns: Changing any namespace id mappings should require privileges

[Serge Hallyn]

Quoting Tim Gardner (tim.gardner at canonical.com):
> Um, file_ns_capable() does not exist in Quantal

Yeah, that is only executed when you write to /proc/self/maps,
which only exists when CONFIG_USERNS=y, which can't be the
case in our kernels yet - not even saucy right now.

So our first CONFIG_USERNS=y kernel should get this fix
automatically from upstream, and no earlier kernels should
need this.

-serge