Stop installing Python in build container

Scope itself doesn't have any Python code.

Disable Python test scheduler in CI
 - we set parallelism=1 so no point scheduling

.circleci/config.yml

@@ -55,7 +55,7 @@ jobs:
     parallelism: 1
     steps:
       - checkout
-      - run: COVERDIR=./coverage make BUILD_IN_CONTAINER=false CODECGEN_UID=23 tests
+      - run: COVERDIR=./coverage NO_SCHEDULER=t make BUILD_IN_CONTAINER=false CODECGEN_UID=23 tests
       - persist_to_workspace:
           root: .
           paths:

backend/Dockerfile

@@ -4,9 +4,9 @@ RUN set -eux; \
    export arch_val="$(dpkg --print-architecture)"; \
    apt-get update && \
    if [ "$arch_val" = "amd64" ]; then \
-     apt-get install -y libpcap-dev time file shellcheck git gcc-arm-linux-gnueabihf curl build-essential python-pip; \
+     apt-get install -y libpcap-dev time file shellcheck git gcc-arm-linux-gnueabihf curl build-essential; \
    else \
-     apt-get install -y libpcap-dev time file shellcheck git curl build-essential python-pip; \
+     apt-get install -y libpcap-dev time file shellcheck git curl build-essential; \
    fi; \
    \
    rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
@@ -36,8 +36,6 @@ RUN export arch_val="$(dpkg --print-architecture)"; \
      mv shfmt /usr/bin; \
    fi;
 
-RUN pip install yapf==0.16.2 flake8==3.3.0 requests==2.19.1
-
 # Install Docker (client only)
 ENV DOCKERVERSION=17.09.1-ce
 RUN export arch_val="$(dpkg --print-architecture)"; \