phosphor-pid-control: srcrev bump 473d68db2a..f81f28860b

James Feist (5):
      dbusconfiguration: set timeout to 0
      stepwise: Add ceiling type
      dbuspassive: allow scaling
      s/minThermalRPM/minThermalOutput
      Expand conf namespace

(From meta-phosphor rev: 9cfe098e2c64b78e3885948347ea985335fa7777)

Change-Id: I04ee3af38cb932960d6a079acf70645d54c97490
Signed-off-by: Andrew Geissler <openbmcbump-github@yahoo.com>
Signed-off-by: Andrew Geissler <geissonator@yahoo.com>