userns: Kill nsown_capable it makes the wrong thing easy

nsown_capable is a special case of ns_capable essentially for just CAP_SETUID and
CAP_SETGID.  For the existing users it doesn't noticably simplify things and
from the suggested patches I have seen it encourages people to do the wrong
thing.  So remove nsown_capable.

Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

diff --cc fs/namespace.c
Simple merge

diff --cc fs/open.c
Simple merge

diff --cc include/linux/capability.h
Simple merge

diff --cc ipc/namespace.c
Simple merge

diff --cc kernel/capability.c
Simple merge

diff --cc kernel/groups.c
Simple merge

diff --cc kernel/pid_namespace.c
Simple merge

diff --cc kernel/sys.c
Simple merge

diff --cc kernel/uid16.c
Simple merge

diff --cc kernel/utsname.c
Simple merge

diff --cc net/core/net_namespace.c
Simple merge

diff --cc net/core/scm.c
Simple merge