Disable the Session log direction on the grill-server end.

Disabling the hive session redirection on the grill-server end to reduce the number of file handles associated with the grill server.
We should disable for grill sessions, not hive sessions. Description should say disabling for grill sessions alone.  Also, I'm thinking should it be a configuration property or always disable? 

@jdhok , Do you see any problem disabling this for grill server?