phosphor-logging: srcrev bump 216999f035..c6ee7c5435

Alpana Kumari (1):
      PEL: Add UnknownSystemType error to message_registry

Andrew Geissler (1):
      openpower-pels: only fail on hw callouts

Matt Spinler (1):
      PEL: Trace when the send-to-host setting changes

Ravi Teja (1):
      Remove emit_object_signal() in restore path

Change-Id: I5881b25b929c63ec6da04fe6299e754c40ba634d
Signed-off-by: Andrew Geissler <openbmcbump-github@yahoo.com>