trivial: SubmittingPatches: Fix reference to renumbered step

This patch fixes a reference to step "Select e-mail destination." which
has been renumbered from 4) to 5) in linux-2.6.22.

Signed-off-by: Michael Brunner <mibru@gmx.de>
Acked-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>