OSX working again on GitHub actions - Fix CI (#1840)

scripts/osx/install_brew.sh

-xcode-select --install
+# In case the command line have already been installed, "true" will make it return a non-zero error code to avoid stopping the scripts
+xcode-select --install || true
 bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install.sh)"
 brew update

scripts/osx/install_deps.sh

-brew install openblas
-brew install -vd snappy leveldb gflags glog szip lmdb
-brew install hdf5 opencv
+#!/bin/bash
+brew_packages="openblas snappy leveldb gflags glog szip lmdb hdf5 opencv protobuf boost cmake viennacl"
+for pkg in $brew_packages
+do
+    echo "brew install $pkg || brew upgrade $pkg"
+    brew install "$pkg" || brew upgrade "$pkg"
+done
+
 # with Python pycaffe needs dependencies built from source
 #brew install --build-from-source --with-python -vd protobuf
 #brew install --build-from-source -vd boost boost-python
 # without Python the usual installation suffices
-brew install protobuf boost
-brew install cmake
-brew install viennacl
-sudo pip install numpy
-sudo pip install opencv-python
+
+pip_packages="numpy<1.17 opencv-python<4.3"
+for pkg in $pip_packages
+do
+    echo "sudo -H python2 -m pip install $pkg"
+    sudo -H python2 -m pip install "$pkg"
+done

scripts/travis/install_deps_osx.sh

@@ -6,5 +6,8 @@ echo "Running on Mac OS."
 BASEDIR=$(dirname $0)
 source $BASEDIR/defaults.sh
 
-bash scripts/osx/install_brew.sh
-bash scripts/osx/install_deps.sh
+# To fix linking issue in CI during install of python as dep of opencv
+[[ -f /usr/local/bin/2to3 ]] && rm -f /usr/local/bin/2to3
+
+source ./scripts/osx/install_brew.sh
+source ./scripts/osx/install_deps.sh