[PATCH] format-patch: fix skipping of blank-lines

[PATCH] format-patch: fix skipping of blank-lines

If it is fed a commit with more than one leading blank lines,
the sed scripts git-format-patch-script used looped forever.
Using git-stripspace upfront makes the sed script somewhat
simpler to work around this problem.

Also use git-rev-parse so that we can say

    $ git-format-patch-script HEAD^^^^

to prepare the latest four patches for e-mail submission.

Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>