Make logging to stdout default and remove symlink

[northys]

I've installed rawmind/alpine-traefik:1.7.7-0 and I wanted to collect traefik logs with telegraf so I've mounted file to ${SERVICE_HOME}/log/traefik.log and ${SERVICE_HOME}/log/access.log but not a single line were written.

Then I've found that you always symlink stdout to the given path. Wouldn't it be better to set default value of log paths to stdout and let user to change it?

I can send PR with symlink removal but first I want to ask if I'm missing something.