Merge branch '7.1' into 7.2

* 7.1:
  do not mix named and positional arguments in data provider definitions
  session names must not be empty
  add missing properties
  fix Contracts directory name in PHPUnit configuration
  [Validator][CidrValidator] Fix error message for `OutOfRangeNetmask` validation
  Passing null to parameter #2 ($subject) of type string is deprecated

Author: xabbuh

Tests/Session/Storage/Handler/AbstractRedisSessionHandlerTestCase.php

@@ -85,7 +85,7 @@ public function testUseSessionGcMaxLifetimeAsTimeToLive()
 
     public function testDestroySession()
     {
-        $this->storage->open('', '');
+        $this->storage->open('', 'test');
         $this->redisClient->set(self::PREFIX.'id', 'foo');
 
         $this->assertTrue((bool) $this->redisClient->exists(self::PREFIX.'id'));

Tests/Session/Storage/Handler/MemcachedSessionHandlerTest.php

@@ -107,7 +107,7 @@ public function testWriteSessionWithLargeTTL()
 
     public function testDestroySession()
     {
-        $this->storage->open('', '');
+        $this->storage->open('', 'sid');
         $this->memcached
             ->expects($this->once())
             ->method('delete')