Support editable virtualenv installation for development

An editable installation allows changes to be made to the source code
directly, and have those changes applied immediately without having to
reinstall.

    pip install -e /path/to/kolla-ansible

Change-Id: I023d96d25edd9d2fafd4415743e298af72a861a1

tools/kolla-ansible

@@ -73,7 +73,12 @@ function find_base_dir {
         elif [[ ${dir_name} == "/usr/local/bin" ]]; then
             BASEDIR=/usr/local/share/kolla-ansible
         elif [[ -n ${VIRTUAL_ENV} ]] && [[ ${dir_name} == "${VIRTUAL_ENV}/bin" ]]; then
-            BASEDIR="${VIRTUAL_ENV}/share/kolla-ansible"
+            if test -f ${VIRTUAL_ENV}/lib/python*/site-packages/kolla-ansible.egg-link; then
+                # Editable install.
+                BASEDIR="$(head -n1 ${VIRTUAL_ENV}/lib/python*/site-packages/kolla-ansible.egg-link)"
+            else
+                BASEDIR="${VIRTUAL_ENV}/share/kolla-ansible"
+            fi
         else
             BASEDIR="$(dirname ${dir_name})"
         fi