send-email: suppress meaningless whitespaces in from field

Remove leading and trailing whitespaces in from field before
interepreting it to improve consistency with other options.  The
split_addrs function already take care of trailing and leading
whitespaces for to, cc and bcc fields.
The from option now:

 - has the same behavior when passing arguments like
   "  jdoe@example.com ", "\t jdoe@example.com " or
   "jdoe@example.com".

 - interprets aliases in string containing leading and trailing
   whitespaces such as " alias" or "alias\t" like other options.

Signed-off-by: Remi Lespinet <remi.lespinet@ensimag.grenoble-inp.fr>
Signed-off-by: Matthieu Moy <Matthieu.Moy@imag.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

git-send-email.perl

@@ -761,6 +761,7 @@ if (!$force) {
 }
 
 if (defined $sender) {
+	$sender =~ s/^\s+|\s+$//g;
 	($sender) = expand_aliases($sender);
 } else {
 	$sender = $repoauthor || $repocommitter || '';

t/t9001-send-email.sh

@@ -1692,4 +1692,28 @@ test_expect_success $PREREQ 'aliases work with email list' '
 	test_cmp expected-list actual-list
 '
 
+test_expect_success $PREREQ 'leading and trailing whitespaces are removed' '
+	echo "alias to2 to2@example.com" >.mutt &&
+	echo "alias cc1 Cc 1 <cc1@example.com>" >>.mutt &&
+	test_config sendemail.aliasesfile ".mutt" &&
+	test_config sendemail.aliasfiletype mutt &&
+	TO1=$(echo "QTo 1 <to1@example.com>" | q_to_tab) &&
+	TO2=$(echo "QZto2" | qz_to_tab_space) &&
+	CC1=$(echo "cc1" | append_cr) &&
+	BCC1=$(echo "Q bcc1@example.com Q" | q_to_nul) &&
+	git send-email \
+	--dry-run \
+	--from="	Example <from@example.com>" \
+	--to="$TO1" \
+	--to="$TO2" \
+	--to="  to3@example.com   " \
+	--cc="$CC1" \
+	--cc="Cc2 <cc2@example.com>" \
+	--bcc="$BCC1" \
+	--bcc="bcc2@example.com" \
+	0001-add-master.patch | replace_variable_fields \
+	>actual-list &&
+	test_cmp expected-list actual-list
+'
+
 test_done