Fix the old, broken docker file for cogserver.

This might fix issue #157.

Not yet tested.

opencog/cogserver/Dockerfile

@@ -3,18 +3,15 @@
 # 2. docker run -p 17001:17001 -it opencog/cogserver
 # 3. rlwrap telnet localhost 17001
 
-FROM opencog/cogutil
-
-# Install non-system project dependencies
-RUN  /tmp/octool -al ; ccache -C
+FROM opencog/base
 
 # Clone opencog and build it
-RUN git clone --depth 1 https://github.com/opencog/opencog oc
-RUN cd oc; mkdir build; cd build; cmake ..; make -j$(nproc)
+RUN git clone --depth 1 https://github.com/opencog/cogserver cogserver
+RUN cd cogserver; mkdir build; cd build; cmake ..; make -j$(nproc)
 
 # Docker defaults
-WORKDIR /home/opencog/oc/build
+WORKDIR /home/opencog/cogserver/build
 USER opencog
 
 ## Start cogserver when container runs
-CMD opencog/server/cogserver
+CMD opencog/cogserver/server/cogserver