am 151b9aa8: am 5d5d7854: Harden UpgradeAccounts against runtime errors (e.g. NPE)

Merge commit '151b9aa8dff6350c9e247579599bf70e1c55eea1' into kraken

* commit '151b9aa8dff6350c9e247579599bf70e1c55eea1':
  Harden UpgradeAccounts against runtime errors (e.g. NPE)