Take over clear balanced_account_uri on absorbed participant.

[zbynekwinkler]

Fixes #1854.

[zbynekwinkler]

Should we also fix the database?

select count(*) 
from participants 
where balanced_account_uri is not null 
and username in (select archived_as from absorptions);

returns

 count 
-------
    38
(1 row)

What worries me is that we are loosing data by this since we do not log (yet) the balanced_account_uri 😟

[chadwhitacre]

@zwn We do have the data in old backups (worst case scenario).

[chadwhitacre]

What if the absorbing account has no balance_account_uri? Do we want to copy over the old balance_account_uri? That's what #818 #941 is about.

[zbynekwinkler]

What if the absorbing account has no balance_account_uri? Do we want to copy over the old balance_account_uri? That's what #941 is about.

I don't know how the balanced api works so I don't know if this is the way to bring over the things registered with them.

[chadwhitacre]

@zwn I think we should close this, because it depends on our strategy wrt take_over and that's far from decided yet (#1948).