send-email: change --no-validate to boolean --[no-]validate

There is also now a configuration variable:

    sendemail[.<identity>].validate

Signed-off-by: Michael Witten <mfwitten@mit.edu>
Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

Documentation/git-send-email.txt

@@ -182,14 +182,16 @@ configuration variable), then authentication is not attempted.
 +
 The --to option must be repeated for each user you want on the to list.
 
---no-validate::
-	Don't perform any sanity checks on patches.
+--[no-]validate::
+	Perform sanity checks on patches.
 	Currently, validation means the following:
 +
 --
 		*	Warn of patches that contain lines longer than 998 characters; this
 			is due to SMTP limits as described by http://www.ietf.org/rfc/rfc2821.txt.
 --
++
+This option can be set with sendemail[.<identity>].validate; default to --validate
 
 
 CONFIGURATION
@@ -242,6 +244,9 @@ sendemail.smtpencryption::
 sendemail.smtpssl::
 	Legacy boolean that sets 'smtpencryption=ssl' if enabled.
 
+sendemail.validate::
+    Boolean override for --[no-]validate.
+
 Author
 ------
 Written by Ryan Anderson <ryan@michonline.com>

git-send-email.perl

@@ -65,7 +65,7 @@ sub usage {
    --smtp-ssl                     * Deprecated. Use '--smtp-encryption ssl'.
    --quiet                        * Output one line of info per email.
    --dry-run                      * Don't actually send the emails.
-   --no-validate                  * Don't perform sanity checks on patches.
+   --[no-]validate                * Perform patch sanity checks. Default on.
 
 EOT
 	exit(1);
@@ -147,14 +147,15 @@ sub format_2822_time {
 my ($thread, $chain_reply_to, $suppress_from, $signed_off_cc, $cc_cmd);
 my ($smtp_server, $smtp_server_port, $smtp_authuser, $smtp_encryption);
 my ($identity, $aliasfiletype, @alias_files, @smtp_host_parts);
-my ($no_validate);
+my ($validate);
 my (@suppress_cc);
 
 my %config_bool_settings = (
     "thread" => [\$thread, 1],
     "chainreplyto" => [\$chain_reply_to, 1],
     "suppressfrom" => [\$suppress_from, undef],
     "signedoffcc" => [\$signed_off_cc, undef],
+    "validate" => [\$validate, 1],
 );
 
 my %config_settings = (
@@ -221,7 +222,7 @@ sub signal_handler {
 		    "dry-run" => \$dry_run,
 		    "envelope-sender=s" => \$envelope_sender,
 		    "thread!" => \$thread,
-		    "no-validate" => \$no_validate,
+		    "validate!" => \$validate,
 	 );
 
 unless ($rc) {
@@ -374,7 +375,7 @@ sub read_config {
 	}
 }
 
-if (!$no_validate) {
+if ($validate) {
 	foreach my $f (@files) {
 		unless (-p $f) {
 			my $error = validate_patch($f);