[alias-server] Patch bug in log.js

Summary:
T2965

Since this app is run on a server with systemctl, we do not need timestamps in logging (already provided by server). Patch bug in log.js where trying to log('someVariable', <someVariable>) would display nothing if <someVariable> === 0 or false

Test Plan: node index.js and no timestamps.

Reviewers: #bitcoin_abc, emack

Reviewed By: #bitcoin_abc, emack

Differential Revision: https://reviews.bitcoinabc.org/D13345