Remove default configuration of Apache

The default configuration was overwriting the configuration added
here. This broke for example longer replication pushes due to too
short timeouts.

Change-Id: I0b20ac10b10ebbdd3e1b89c847fea8afb9fb74db
diff --git a/container-images/apache-git-http-backend/Dockerfile b/container-images/apache-git-http-backend/Dockerfile
index 1613007..9b3d1a0 100644
--- a/container-images/apache-git-http-backend/Dockerfile
+++ b/container-images/apache-git-http-backend/Dockerfile
@@ -7,7 +7,8 @@
       apache2-ctl \
       apache2-utils \
       apache2-ssl \
-      git-daemon
+      git-daemon && \
+    rm /etc/apache2/conf.d/default.conf
 
 # Configure git-http-backend
 COPY config/git-https-backend.conf /etc/apache2/conf.d/