Put back MSG_TYPE_TAPEMOUNTEDFORRECALL and MSG_TYPE_TAPEUNMOUNTSTARTED.

These two message types were incorrectly removed by the
following commit back in 2016:

commit bedf9832
Author: Eric Cano <Eric.Cano@cern.ch>
Date:   Wed Aug 24 14:47:06 2016 +0200

    Moved and renamed TapeserverProxy class as TapedProxy.

    Added new functions allowing representation of the full life cycle of the tape sessions.
    Phased out the first old function (gotArchiveJobFromCTA).
    Removed some dead code.