do not install whole anaconda by default

defaults/main.yml

@@ -3,4 +3,4 @@ conda_directory: /opt/conda
 conda_installer_url: https://repo.continuum.io/miniconda/Miniconda3-4.5.11-Linux-x86_64.sh
 conda_installer_checksum: sha256:ea4594241e13a2671c5b158b3b813f0794fe58d514795fbf72a1aad24db918cf
 
-conda_anaconda_env: true
+conda_anaconda_env: false