funding: properly display pending chan ID within logs
funding: properly display pending chan ID within logs

This commit corrects a minor formatting error when logging the pending
channel ID within the logs. Previously, the logging directives and
parameter could cause the pending chan ID to display in a double-hex
encoded format. We fix this by ensuring that we properly slice the chan
ID before printing it, and also ensure that we use the %x formatting
(which will hex encode the bytes) everywhere.

Fixes #331.

aakselrod/lnd,LightningNetwork/lnd,aakselrod/lnd,ddustin/lnd,LightningNetwork/lnd,ddustin/lnd