Resolve "CentOS7 image with ROOT 6.20.04 not building"

base/centos-full-root6.20.04:7

@@ -14,20 +14,21 @@ FROM docker.km3net.de/base/centos:7
  RUN curl -L http://proj-clhep.web.cern.ch/proj-clhep/DISTRIBUTION/tarFiles/clhep-2.2.0.8-x86_64-cc7-gcc48-opt.tgz > clhep.tgz && tar -C /usr/local/ --strip-components=1 -xvzf clhep.tgz
 
 # aart: root requires python-devel.
- RUN yum install -y rh-python36-python-devel
-
- RUN echo 'export LD_LIBRARY_PATH=/opt/rh/rh-python36/root/usr/lib64:$LD_LIBRARY_PATH' >> /etc/profile.d/python36.sh
- RUN echo "export X_SCLS=rh-python36" >> /etc/profile.d/python36.sh
- RUN echo 'export PATH=/opt/rh/rh-python36/root/usr/bin:$PATH' >> /etc/profile.d/python36.sh
- RUN echo 'export XDG_DATA_DIRS=/opt/rh/rh-python36/root/usr/share:/usr/local/share:/usr/share' >> /etc/profile.d/python36.sh
- RUN echo 'export PKG_CONFIG_PATH=/opt/rh/rh-python36/root/usr/lib64/pkgconfig' >> /etc/profile.d/python36.sh
- RUN source /etc/profile.d/python36.sh && pip install -U pip setuptools
+ RUN yum install -y rh-python36-python-devel && \
+     echo 'export LD_LIBRARY_PATH=/opt/rh/rh-python36/root/usr/lib64:$LD_LIBRARY_PATH' > /etc/profile.d/python36.sh &&  \
+     echo "export X_SCLS=rh-python36" >> /etc/profile.d/python36.sh &&  \
+     echo 'export PATH=/opt/rh/rh-python36/root/usr/bin:$PATH' >> /etc/profile.d/python36.sh &&  \
+     echo 'export XDG_DATA_DIRS=/opt/rh/rh-python36/root/usr/share:/usr/local/share:/usr/share' >> /etc/profile.d/python36.sh &&  \
+     echo 'export PKG_CONFIG_PATH=/opt/rh/rh-python36/root/usr/lib64/pkgconfig' >> /etc/profile.d/python36.sh &&  \
+     source /etc/profile.d/python36.sh && python3 -m pip install pip==20.1 setuptools==46.3.0 numpy==1.18.4
 
  RUN yum install -y log4cpp log4cpp-devel libxml2 libxml2-devel gsl gsl-devel
+ 
 #lhapdf
  RUN cd / && curl -L https://lhapdf.hepforge.org/downloads/\?f\=lhapdf-5.9.1.tar.gz > lhapdf-5.9.1.tar.gz && \
     tar xzvf lhapdf-5.9.1.tar.gz && cd lhapdf-5.9.1 && \
     ./configure --prefix=/usr/local && make && make install
+    
 #Pythia 6.4.28 (using script in GENIE)
 #https://root-forum.cern.ch/t/root-with-pythia6-and-pythia8/19211/4
  RUN cd / && wget https://root.cern.ch/download/pythia6.tar.gz && \
@@ -37,13 +38,6 @@ FROM docker.km3net.de/base/centos:7
     mv pythia6 pythia6428 && cd pythia6428 && \
     ./makePythia6.linuxx8664 && echo "export PYTHIA6=/pythia6428" > /etc/profile.d/genie.sh
 
-# aart: there'ss is a bug in the the root cmake procedure that fires when numpy is not found
-# so just install it, I guess...
-# see https://github.com/root-project/root/commit/89c089127f9ac57ca45348f7ac8c71624b68955d
-
-RUN python3 -m pip install numpy 
-ENV PYTHONPATH="/usr/local/lib64/python3.6/site-packages:${PYTHONPATH}"
-
 #ROOT6
 RUN source /etc/profile.d/genie.sh && cd / && rm -rf /usr/local/root && \
    export ROOT_VERSION=6.20.04 && \