[PATCH] revert the /proc thread visibility fix

It appears that gdb, perfmon and perhaps other applications are already
opening /proc/<tid> even though it does not appear in /proc readdir output
and is available under its group leader's directory anyway.

Apparently ascertaining the group leader is hard for gdb and thsi trick
always worked for LinuxThreads apps.

So revert this change.

fs/proc/base.c

@@ -1582,13 +1582,14 @@ struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, struct
 	read_unlock(&tasklist_lock);
 	if (!task)
 		goto out;
-	if (!thread_group_leader(task))
-		goto out_drop_task;
 
 	inode = proc_pid_make_inode(dir->i_sb, task, PROC_TGID_INO);
 
-	if (!inode)
-		goto out_drop_task;
+
+	if (!inode) {
+		put_task_struct(task);
+		goto out;
+	}
 	inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
 	inode->i_op = &proc_tgid_base_inode_operations;
 	inode->i_fop = &proc_tgid_base_operations;
@@ -1613,8 +1614,6 @@ struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, struct
 		goto out;
 	}
 	return NULL;
-out_drop_task:
-	put_task_struct(task);
 out:
 	return ERR_PTR(-ENOENT);
 }