send-email: use Perl idioms in while loop

send-email: use Perl idioms in while loop

Change `while(<$fh>) { my $c = $_' to `while(my $c = <$fh>) {', and
use `chomp $c' instead of `$c =~ s/\n$//g;', the two are equivalent in
this case.

I've also changed the --cccmd test so that we test for the stripping
of whitespace at the beginning of the lines returned from the
--cccmd. I think we probably shouldn't do this, but it was there
already so I haven't changed the behavior.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.comReviewed-by: Avery Pennarun <apenwarr@gmail.com>
Reviewed-by: Jeff King <peff@peff.net>
>
Signed-off-by: Junio C Hamano <gitster@pobox.com>