Upgrade docker images to use Python 3

Issue-ID: SDC-4456
Signed-off-by: eschcam <cameron.scholes@est.tech>
Change-Id: Ifa83fa9bc889920b9d29058870981a0ae0364240
diff --git a/openecomp-be/dist/sdc-onboard-db-init-docker/artifacts/Dockerfile b/openecomp-be/dist/sdc-onboard-db-init-docker/artifacts/Dockerfile
index ce5fc02..d2307b1 100644
--- a/openecomp-be/dist/sdc-onboard-db-init-docker/artifacts/Dockerfile
+++ b/openecomp-be/dist/sdc-onboard-db-init-docker/artifacts/Dockerfile
@@ -8,9 +8,11 @@
     echo  'version=3.4.4' >> ~/.cassandra/cqlshrc
 USER root
 
-RUN apt-get update --allow-releaseinfo-change && apt-get install -y python-pip && \
-    python -m pip install --upgrade pip \
-    pip install cqlsh==6.0.0 && \
+RUN apt-get update --allow-releaseinfo-change &&  \
+    apt-get purge python* -y && \
+    apt-get install -y python3-pip && \
+    python3 -m pip install --upgrade pip && \
+    pip3 install cqlsh==6.1.0 && \
     mkdir ~/.cassandra/ && \
     echo  '[cql]' > ~/.cassandra/cqlshrc  && \
     echo  'version=3.4.4' >> ~/.cassandra/cqlshrc  && \