Fix docker build, include tls.Config in http.Server

[sdsznsk]

When merged this pull request will:

• Fix error in local docker build

$ git clone https://github.com/jpweber/cole.git
$ cd cole
$ docker build -t cole .
---------- SNIP --------------
Step 6/12 : RUN CGO_ENABLED=0 go build -a -ldflags '-s' -installsuffix cgo -o app .
 ---> Running in 92fe8e2f38e9
# github.com/jpweber/cole
./main.go:126:2: invalid character U+0023 '#'
./main.go:127:7: no new variables on left side of :=
The command '/bin/sh -c CGO_ENABLED=0 go build -a -ldflags '-s' -installsuffix cgo -o app .' returned a non-zero code: 2

• Include defined tls.Config in http.Server

Resolves #11