Quieting down shepherd logging if no cache instance found

Hello @eford1, @skuwamoto, 

Please review the following commits I made in branch 'azulus-logging'.

adca5af828d0bdee38062f5811edf3fc25823b70 (2013-05-28 10:49:13 -0700)
Quieting down unnecessary logging


R=@eford1
R=@skuwamoto