am c5f4f732: Use "unknown" as the default value for the client id to avoid crashing.

Merge commit 'c5f4f732aea6303e5c3630d982847a26d41715f5'

* commit 'c5f4f732aea6303e5c3630d982847a26d41715f5':
  Use "unknown" as the default value for the client id to avoid crashing.