[tests] Relax checks on invalid expire time messages.

Previously there was a bug in Redis that returned the wrong command
in -ERR messages when passing an invalid expire time with SETEX and
PSETEX. Now that the bug has been fixed and that travis-ci uses a an
updated version of Redis, our test suite turned red.

tests/Predis/Command/StringPreciseSetExpireTest.php

@@ -93,8 +93,7 @@ class StringPreciseSetExpireTest extends PredisCommandTestCase
     /**
      * @group connected
      * @expectedException \Predis\Response\ServerException
-     * @expectedExceptionMessage ERR invalid expire time in SETEX
-     * @todo Should not Redis return PSETEX instead of SETEX here?
+     * @expectedExceptionMessage ERR invalid expire time
      */
     public function testThrowsExceptionOnZeroTTL()
     {
@@ -104,8 +103,7 @@ class StringPreciseSetExpireTest extends PredisCommandTestCase
     /**
      * @group connected
      * @expectedException \Predis\Response\ServerException
-     * @expectedExceptionMessage ERR invalid expire time in SETEX
-     * @todo Should not Redis return PSETEX instead of SETEX here?
+     * @expectedExceptionMessage ERR invalid expire time
      */
     public function testThrowsExceptionOnNegativeTTL()
     {

tests/Predis/Command/StringSetExpireTest.php

@@ -94,7 +94,7 @@ class StringSetExpireTest extends PredisCommandTestCase
     /**
      * @group connected
      * @expectedException \Predis\Response\ServerException
-     * @expectedExceptionMessage ERR invalid expire time in SETEX
+     * @expectedExceptionMessage ERR invalid expire time
      */
     public function testThrowsExceptionOnZeroTTL()
     {
@@ -104,7 +104,7 @@ class StringSetExpireTest extends PredisCommandTestCase
     /**
      * @group connected
      * @expectedException \Predis\Response\ServerException
-     * @expectedExceptionMessage ERR invalid expire time in SETEX
+     * @expectedExceptionMessage ERR invalid expire time
      */
     public function testThrowsExceptionOnNegativeTTL()
     {