add /usr/share/qgis/python/plugins to PYTHONPATH (#8877)

mbernasocchi · nyalldawson · commit d3c04c20e31d · 2019-01-18T12:56:19.000+11:00
this is needed to find the correct processing (and db_manager and metasearch) (cherry picked from commit 6896ce9)
diff --git a/.docker/qgis.dockerfile b/.docker/qgis.dockerfile
@@ -65,7 +65,7 @@ COPY .docker/qgis_resources/supervisor/supervisor.xvfb.conf /etc/supervisor/supe
 # - deb installed
 # - built from git
 # needed to find PyQt wrapper provided by QGIS
-ENV PYTHONPATH=/usr/share/qgis/python/:/usr/lib/python3/dist-packages/qgis:/usr/share/qgis/python/qgis
+ENV PYTHONPATH=/usr/share/qgis/python/:/usr/share/qgis/python/plugins:/usr/lib/python3/dist-packages/qgis:/usr/share/qgis/python/qgis
 
 
 WORKDIR /
