Pidns: make full use of xxx_vnr() calls

Some time ago the xxx_vnr() calls (e.g.  pid_vnr or find_task_by_vpid) were
_all_ converted to operate on the current pid namespace.  After this each call
like xxx_nr_ns(foo, current->nsproxy->pid_ns) is nothing but a xxx_vnr(foo)
one.

Switch all the xxx_nr_ns() callers to use the xxx_vnr() calls where
appropriate.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Reviewed-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/fcntl.c b/fs/fcntl.c
index 8685263..7efe59e 100644
--- a/fs/fcntl.c
+++ b/fs/fcntl.c
@@ -309,7 +309,7 @@
 {
 	pid_t pid;
 	read_lock(&filp->f_owner.lock);
-	pid = pid_nr_ns(filp->f_owner.pid, current->nsproxy->pid_ns);
+	pid = pid_vnr(filp->f_owner.pid);
 	if (filp->f_owner.pid_type == PIDTYPE_PGID)
 		pid = -pid;
 	read_unlock(&filp->f_owner.lock);