arch/alpha/boot/tools/objstrip.c: wrong variable tested after open()

The incorrect variable is tested. fd is used for another open()
and is already tested.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Richard Henderson <rth@twiddle.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>