build: use RELEASE as qualifier for non-SNAPSHOT versions

Change-Id: I6b01a824ae1cd3a4e2c8c6dee18fae16153acdb6
Reviewed-on: http://gerrit.esdi-community.eu/3172
Tested-by: Jenkins <sitemple@igd.fraunhofer.de>
Reviewed-by: Simon Templer <simon.templer@igd.fraunhofer.de>