send-email: do not reverse the command line arguments

The loop picks elements from @ARGV one by one, sifts them into arguments
meant for format-patch and the script itself, and pushes them to @files
and @rev_list_opts arrays.  Pick elements from @ARGV starting at the
beginning using shift, instead of at the end using pop, as push appends
them to the end of the array.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

git-send-email.perl

@@ -421,7 +421,7 @@ EOF
 # Now that all the defaults are set, process the rest of the command line
 # arguments and collect up the files that need to be processed.
 my @rev_list_opts;
-while (my $f = pop @ARGV) {
+while (defined(my $f = shift @ARGV)) {
 	if ($f eq "--") {
 		push @rev_list_opts, "--", @ARGV;
 		@ARGV = ();