Bug 1364: Preserve flow entries during container mode.

Flow entries in the default container should be preserved when the contoller
enters the container mode.

  * Ignore FLOW_REMOVED in the default container during container mode.
  * Data flow APIs behave as if no data flow is installed in the default
    container during container mode.

Change-Id: Ia999160aa123ea062f8d36af1eb072c44bf77e4c
Signed-off-by: Shigeru Yasuda <s-yasuda@da.jp.nec.com>
Merge "Bug 1364: Preserve flow entries during container mode."