Merge pull request #3292 from yasonk/fix-exec_run-doc

fixing doc for stream param in exec_run

Author: thaJeztah

docker/models/containers.py

@@ -181,7 +181,8 @@ def exec_run(self, cmd, stdout=True, stderr=True, stdin=False, tty=False,
             user (str): User to execute command as. Default: root
             detach (bool): If true, detach from the exec command.
                 Default: False
-            stream (bool): Stream response data. Default: False
+            stream (bool): Stream response data. Ignored if ``detach`` is true.
+                Default: False
             socket (bool): Return the connection socket to allow custom
                 read/write operations. Default: False
             environment (dict or list): A dictionary or a list of strings in