When a user tries to add a router from 1 project to a FW from another,
the driver should through InternalDriverError for hte FW to be in ERROR state.
This should not be done in case of a delete action, in order to allow
the deletion of an ERROR FW as well.
Commit Ia86ccc7906ff58b35dccb01f4c165822b9dbf2a9 removed the InternalDriverError
in a wrong attempt to handle the deletion case.
Change-Id: I2c88c6ff773235876253a0b194d30d1d417e03c4
48004c8806