Really fix #4039

A typo from 8df6efd402180a6361b4dd619f5535d6c2bed334
diff --git a/system/libraries/Session/drivers/Session_files_driver.php b/system/libraries/Session/drivers/Session_files_driver.php
index f0f055f..1a943d5 100644
--- a/system/libraries/Session/drivers/Session_files_driver.php
+++ b/system/libraries/Session/drivers/Session_files_driver.php
@@ -185,7 +185,7 @@
 		}
 		// We shouldn't need this, but apparently we do ...
 		// See https://github.com/bcit-ci/CodeIgniter/issues/4039
-		elseif ($this->_file_handler === FALSE)
+		elseif ($this->_file_handle === FALSE)
 		{
 			return $this->_failure;
 		}