Sometimes deleting a content leaves the keystore corrupted

[stcarrez]

With the following scenario, the keystore becomes corrupted after removal of an item:

  bin/akt create test.akt -c 10:100 -p admin --force
  bin/akt store test.akt -p admin toto
  bin/akt store test.akt -p admin titi
  bin/akt list test.akt -p admin
  bin/akt remove test.akt -p admin toto

Removing 'titi' first does not corrupt the keystore.

[stcarrez]

There is still a case where removing a content invalidates the key of another content which is weird.
With the following sequence:

akt set bug.akt property-1 value-1
akt set bug.akt property-2 value-2
akt set bug.akt property-3 value-3
akt remove bug.akt property-2

The property-3 becomes unreadable because property-2 was removed and we incorrectly updated the key area.