CMFileManager: Fix typo in the default string

  <string name="msgs_operation_can_not_be_cancelled">The operation cannot be cancelled.</string>

  <!-- The operation requieres mount the file system prior to execute the command -->

  <string name="msgs_read_only_filesystem">The file system is read-only. Try to mount the

    file system as read-write before attepting the operation.</string>

    file system as read-write before attempting the operation.</string>

  <!-- Illegal argument (normally caused by a development error when calling internal api) -->

  <string name="msgs_illegal_argument">Illegal argument. Invocation failed.</string>

  <!-- The operation will cause inconsistencies -->