Return false if creating a temporary file fails

Author: JaZo

src/EncryptedAdapter.php

@@ -148,6 +148,11 @@ public function readStream($path)
         }
 
         $stream = tmpfile();
+
+        if ($stream === false) {
+            return false;
+        }
+
         fwrite($stream, $result['contents']);
         fseek($stream, 0);
         unset($result['contents']);