container: use policy name in log message

This is more helpful than having the user resolve the integer.

Signed-off-by: Ophestra <cat@gensokyo.uk>

container/container.go

@@ -385,7 +385,7 @@ func (p *Container) Start() error {
 					param.priority = priority
 				}
 
-				p.msg.Verbosef("setting scheduling policy %d", p.SchedPolicy)
+				p.msg.Verbosef("setting scheduling policy %s", p.SchedPolicy)
 				if err := schedSetscheduler(
 					0, // calling thread
 					p.SchedPolicy,