OBS: specify setuptools version (44.1.1)

With previous version of setuptools (33.1.1), we have errors when downloading the latest version:

While:
  Bootstrapping.
  Getting distribution for 'setuptools==44.1.1'.
Error: https://files.pythonhosted.org/packages/b2/40/4e00501c204b457f10fe410da0c97537214b2265247bc9a5bc6edd55b9e4/setuptools-44.1.1.zip#sha256=c67aa55db532a0dadc4d2e20ba9961cbd3ccc84d544e9029699822542b5a476b hostname 'files.pythonhosted.org' doesn't match 'r.ssl.fastly.net'

obs/slapos/prepare_download_cache.sh

@@ -27,10 +27,12 @@ sed  "s/\%RECIPE_VERSION\%/$RECIPE_VERSION/g;s|\%PATCHES_DIRECTORY\%|$PATCHES_DI
 cd $NETWORKCACHED_DIRECTORY
 # Download  bootstrap file
 wget https://bootstrap.pypa.io/bootstrap-buildout.py -O bootstrap.py
-(python2.7 -S bootstrap.py --buildout-version $BUILDOUT_VERSION \
+(python2.7 -S bootstrap.py \
+  --buildout-version $BUILDOUT_VERSION \
+  --setuptools-version 44.1.1 \
   --setuptools-to-dir eggs \
   -f http://www.nexedi.org/static/packages/source/slapos.buildout/ && \
-    ./bin/buildout -v)
+./bin/buildout -v)
 
 # build locally everything with gcc
 sed  "s/\%RECIPE_VERSION\%/$RECIPE_VERSION/g;s|\%PATCHES_DIRECTORY\%|$PATCHES_DIRECTORY|g;s|\%TARGET_DIRECTORY\%|$TARGET_DIRECTORY|g;s|\%BUILD_ROOT_DIRECTORY\%|$BUILD_ROOT_DIRECTORY|g;s|\%BUILD_DIRECTORY\%|$BUILD_DIRECTORY|g" $BUILD_ROOT_DIRECTORY/../buildout_with_gcc.cfg.in > $BUILD_DIRECTORY/buildout.cfg