Fix image tag in full_install_osm, helm chart and install_osm

Change-Id: I7e423bc348feb6cc4a847f42e1de938fb7d30119
Signed-off-by: garciadeblas <gerardo.garciadeblas@telefonica.com>
diff --git a/installers/install_osm.sh b/installers/install_osm.sh
index 2364421..092b38c 100755
--- a/installers/install_osm.sh
+++ b/installers/install_osm.sh
@@ -15,7 +15,7 @@
 REPOSITORY_BASE=https://osm-download.etsi.org/repository/osm/debian
 RELEASE=ReleaseFIFTEEN
 REPOSITORY=stable
-DOCKER_TAG="testing-daily"
+DOCKER_TAG="15"
 DEVOPS_PATH=/usr/share/osm-devops
 
 function usage(){