Stick bundler version to avoid Travis build issue and uninitialized cst

Avoir error:
  uninitialized constant Bundler::RubygemsIntegration::Gem

Author: benoittgt

script/update_rubygems_and_install_bundler

@@ -6,8 +6,18 @@ set -e
 source script/functions.sh
 
 if is_ruby_23_plus; then
-  gem update --system
-  gem install bundler
+  yes | gem update --system
+  # Avoid Bundler error with 2.1.0
+  echo "Warning dowgrading to older version of Bundler"
+  echo "Current bundler versions installed: `gem list | grep '^bundler ('`"
+
+  gem uninstall -aIx bundler || echo "Warning error occured removing bundler via gem"
+
+  rvm @global do gem uninstall -aIx bundler || echo "Warning error occured removing bundler via rvm"
+
+  echo "Bundler version list after uninstall: `gem list | grep '^bundler ('`"
+
+  gem install bundler -v '2.0.2'
 else
   echo "Warning installing older versions of Rubygems / Bundler"
   gem update --system '2.7.8'