base-image: Remove virtualenv installed using pip

Remove triple installations of pip. Pip tool is
installed once using tdnf and other two times
using pip, so rely only on the one installed using
tdnf.

Signed-off-by: Suraj Deshmukh <suraj.deshmukh@microsoft.com>

Author: surajssd

linux/base.Dockerfile

@@ -1,5 +1,5 @@
-# base.Dockerfile contains components which are large and change less frequently. 
-# tools.Dockerfile contains the smaller, more frequently-updated components. 
+# base.Dockerfile contains components which are large and change less frequently.
+# tools.Dockerfile contains the smaller, more frequently-updated components.
 
 # Within Azure, the image layers
 # built from this file are cached in a number of locations to speed up container startup time. A manual
@@ -171,7 +171,6 @@ RUN pip3 install --upgrade sfctl \
 # Install Blobxfer and Batch-Shipyard in isolated virtualenvs
 COPY ./linux/blobxfer /usr/local/bin
 RUN chmod 755 /usr/local/bin/blobxfer \
-  && pip3 install virtualenv \
   && cd /opt \
   && virtualenv -p python3 blobxfer \
   && /bin/bash -c "source blobxfer/bin/activate && pip3 install blobxfer && deactivate"
@@ -196,7 +195,6 @@ RUN curl -fSsL `curl -fSsL https://api.github.com/repos/Azure/batch-shipyard/rel
 # # BEGIN: Install Ansible in isolated Virtual Environment
 COPY ./linux/ansible/ansible*  /usr/local/bin/
 RUN chmod 755 /usr/local/bin/ansible* \
-  && pip3 install virtualenv \
   && cd /opt \
   && virtualenv -p python3 ansible \
   && /bin/bash -c "source ansible/bin/activate && pip3 install ansible && pip3 install pywinrm\>\=0\.2\.2 && deactivate" \