Tests: adjust TODOs for smtp fixes committed in 1.5.6.

mail_smtp.t

diff --git a/mail_smtp.t b/mail_smtp.t
index 5fa7cf1..442b11b 100644
--- a/mail_smtp.t
+++ b/mail_smtp.t
@@ -141,7 +141,7 @@
 # Try auth plain with pipelining
 
 TODO: {
-local $TODO = 'pipelining not in official nginx';
+local $TODO = 'not yet' unless $t->has_version('1.5.6');
 local $SIG{__WARN__} = sub {};
 
 $s = Test::Nginx::SMTP->new();
@@ -198,7 +198,7 @@
 $s->ok('pipelined mail from');
 
 TODO: {
-local $TODO = 'pipelining not in official nginx';
+local $TODO = 'not yet' unless $t->has_version('1.5.6');
 local $SIG{__WARN__} = sub {};
 
 $s->ok('pipelined rcpt to');

mail_smtp_greeting_delay.t

diff --git a/mail_smtp_greeting_delay.t b/mail_smtp_greeting_delay.t
index 3a59f6a..05a313f 100644
--- a/mail_smtp_greeting_delay.t
+++ b/mail_smtp_greeting_delay.t
@@ -60,7 +60,7 @@
 $s->check(qr/^5.. /, "command before greeting - session must be rejected");
 
 TODO: {
-local $TODO = 'not in official nginx yet';
+local $TODO = 'not yet' unless $t->has_version('1.5.6');
 
 ok($s->eof(), "session have to be closed");