Refactor Dockerfile.qa

Optimized so less volatile changes are done first (to take advantage
of docker's image caching when possible) and changed the default command
to use the Makefile targets for QA test suite.

Author: placer14

Dockerfile.qa

@@ -1,23 +1,16 @@
 FROM golang:1.11
-VOLUME /var/lib/openbazaar
 
-ENV BITCOIN_VERSION=0.16.3
+ENV BITCOIND_VERSION=0.16.3
+ENV BITCOIND_PATH=/opt/bitcoin-${BITCOIND_VERSION}
 
-WORKDIR /go/src/github.com/OpenBazaar/openbazaar-go
-
-COPY . .
-
-# software installs:
-# apt-get installs + compile python 3.6 & protobuf
-RUN apt-get -y update
-RUN apt-get -y install software-properties-common
-RUN apt-get install -yq zlib1g-dev libssl-dev unzip
-RUN apt-get install -y python3 python3-pip
-
-RUN python3 -m pip install --upgrade pip && \
-    pip install -r ./qa/requirements.txt && \
-    wget https://bitcoin.org/bin/bitcoin-core-0.16.3/bitcoin-0.16.3-x86_64-linux-gnu.tar.gz && \
-    tar -xvzf bitcoin-0.16.3-x86_64-linux-gnu.tar.gz -C /opt
+# software installs, from most stable to most volatile
+RUN apt-get update -y
+RUN apt-get install -yq software-properties-common \
+                        zlib1g-dev \
+                        libssl-dev \
+                        unzip \
+                        python3 \
+                        python3-pip
 
 RUN wget https://github.com/google/protobuf/releases/download/v3.6.0/protoc-3.6.0-linux-x86_64.zip && \
     unzip ./protoc-3.6.0-linux-x86_64.zip -x readme.txt && \
@@ -37,8 +30,15 @@ RUN git checkout tags/v1.2.0 -b v1.2.0 && \
     cd protoc-gen-go && \
     go install
 
-# build current version of OpenBazaar
+COPY ./qa/requirements.txt ./requirements.txt
+
+RUN python3 -m pip install --upgrade pip && \
+    pip install -r ./requirements.txt && \
+    wget https://bitcoin.org/bin/bitcoin-core-0.16.3/bitcoin-${BITCOIND_VERSION}-x86_64-linux-gnu.tar.gz && \
+    tar -xvzf bitcoin-${BITCOIND_VERSION}-x86_64-linux-gnu.tar.gz -C /opt
+
 WORKDIR /go/src/github.com/OpenBazaar/openbazaar-go
-# RUN go build -o /opt/openbazaard .
+COPY ./Makefile ./Makefile
+VOLUME /go/src/github.com/OpenBazaar/openbazaar-go
 
-ENTRYPOINT ["/go/src/github.com/OpenBazaar/openbazaar-go/build_qa.sh"]
+CMD make qa