corrupt: sha-1 of reconstructed text does not match expected sha-1

[Olivier R-D]

It looks like after upgrading and doing a "bzr upgrade --2a" then the 
merge succeeded ...
but still it is quite scariying problem, the bazaar database got 
completely corrupted by the failing merge and if I did not have had a 
backup of it I could have lost a lot.

is 2a format reliable ? anyway I will redo a checkout in the default 
format to be sure.