order of <<ipsec add>> (orient) vs <<ip link>> vs <<ip addr>>

1. existing ipsec-interface with address

   <<ip link>> create the naked ipsec-interface
   <<ip addr>> adds the address
   <<ipsec add>> (orient) finds and saves the existing interface.
   <<ipsec up>> finds and saves the existing address.

   Since everything is pre-existing, <<ipsec delete>> leaves
   everything behind.

2. existing ipsec-interface with no address

   <<ip link>> create the naked ipsec-interface
   <<ipsec add>> (orient) finds and saves the existing interface.
   <<ipsec up>> adds the missing address

   During <<ipsec delete>>:

   - since pluto added the address it is removed

   - since pluto found the interface that is left behind

3. missing ipsec-interface, yet with addresses

   <<ipsec add>> creates the missing ipsec-interface
   <<ip addr>> adds the address
   <<ipsec up>> finds and saves the existing address.

   During <<ipsec delete>>

   - since pluto did not add the address it is left behind

   - since pluto did create the interface it is deleted (which of
     course deletes the address

... and (bug) trying to fix things by deleting the interface and
re-adding the connection still fails:

see #1771 after ip link add ipsec1; ipsec add ... connection becomes unloadable
