[PATCH] copy_thread(): unneeded child_tid initialization

[PATCH] copy_thread(): unneeded child_tid initialization

{set,clear}_child_tid initialized in copy_process() right after return from
copy_thread().

These vars are not used in cleanup path if copy_thread() fails.

grep -r _child_tid arch/ shows only ia64/kernel/asm-offsets.c,
so i blindly patched non i386 archs too.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>