[REF] Odoo 8.0-10.0: install needed dependencies for worker mode

ie python-gevent and psycogreen. As psycogreen is not packaged in
debian jessie we have to install it with pip. As python-gevent is in the
recommanded packaged of odoo and we don't install them, we install it
explicitely.

10.0/Dockerfile

@@ -8,6 +8,8 @@ RUN set -x; \
             ca-certificates \
             curl \
             node-less \
+            python-gevent \
+            python-pip \
             python-pyinotify \
             python-renderpm \
             python-support \
@@ -16,7 +18,8 @@ RUN set -x; \
         && dpkg --force-depends -i wkhtmltox.deb \
         && apt-get -y install -f --no-install-recommends \
         && apt-get purge -y --auto-remove -o APT::AutoRemove::RecommendsImportant=false -o APT::AutoRemove::SuggestsImportant=false npm \
-        && rm -rf /var/lib/apt/lists/* wkhtmltox.deb
+        && rm -rf /var/lib/apt/lists/* wkhtmltox.deb \
+        && pip install psycogreen==1.0
 
 # Install Odoo
 ENV ODOO_VERSION 10.0