unit-test: Socks proxy support while building the container

This makes it possible for build-unit-test to respect the HTTP{,S}_PROXY
environment variables passed from the docker engine. We had to switch
from wget to curl because the ubuntu wget doesn't understand as many
proxy protocols as curl. The python pip command's use of internal http
libraries requires the python-socks dependency for this to work.

Change-Id: Iae2b0a0a0573c0b80552b070149420fc1c844350
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/build-unit-test-docker.sh b/build-unit-test-docker.sh
index 680ce2d..401cc71 100755
--- a/build-unit-test-docker.sh
+++ b/build-unit-test-docker.sh
@@ -78,6 +78,7 @@
     python-mako \
     python-pip \
     python-setuptools \
+    python-socks \
     python3 \
     python3-dev\
     python3-yaml \
@@ -93,7 +94,7 @@
     libevdev-dev \
     libevdev2-dbgsym \
     sudo \
-    wget \
+    curl \
     git \
     dbus \
     iputils-ping \
@@ -112,17 +113,17 @@
 RUN pip install pycodestyle
 
 # Snapshot from 2018-06-14
-RUN wget -O googletest.tar.gz https://github.com/google/googletest/archive/ba96d0b1161f540656efdaed035b3c062b60e006.tar.gz
+RUN curl -L -o googletest.tar.gz https://github.com/google/googletest/archive/ba96d0b1161f540656efdaed035b3c062b60e006.tar.gz
 RUN tar -xzf googletest.tar.gz
 RUN cd googletest-* && \
 cmake -DBUILD_GTEST=ON -DBUILD_GMOCK=ON -DCMAKE_BUILD_TYPE=RelWithDebInfo -DBUILD_SHARED_LIBS=ON -DCMAKE_INSTALL_PREFIX:PATH=/usr . && \
 make && make install
 
-RUN wget https://github.com/USCiLab/cereal/archive/v1.2.2.tar.gz
+RUN curl -L -O https://github.com/USCiLab/cereal/archive/v1.2.2.tar.gz
 RUN tar -xzf v1.2.2.tar.gz
 RUN cp -a cereal-1.2.2/include/cereal/ /usr/include/
 
-RUN wget https://github.com/nlohmann/json/releases/download/v3.0.1/json.hpp
+RUN curl -L -O https://github.com/nlohmann/json/releases/download/v3.0.1/json.hpp
 RUN mkdir /usr/include/nlohmann/
 RUN cp -a json.hpp /usr/include/nlohmann/