Another fix for the Dockerfile and build (#188)

* Dockerfile: fix

ENTRYPOINT must be provided in exec form for args
from docker run to be passed correctly.

See https://docs.docker.com/engine/reference/builder/#cmd

* build: fix reuse of vscode repository regression

See #167

Dockerfile

@@ -28,5 +28,4 @@ RUN apt-get install -y locales && \
 # We unfortunately cannot use update-locale because docker will not use the env variables
 # configured in /etc/default/locale so we need to set it manually.
 ENV LANG=en_US.UTF-8
-ENTRYPOINT code-server
-CMD ["."]
+ENTRYPOINT ["code-server"]