Changes required to launch RelFOUR: checkout latest stable tag, updated deb release and repo, some checks

Change-Id: I6d1bb7eff17481e5e9fcbdb60e55c0b3c61824db
Signed-off-by: garciadeblas <gerardo.garciadeblas@telefonica.com>
diff --git a/installers/install_osm.sh b/installers/install_osm.sh
index 9b2e975..731cfbd 100755
--- a/installers/install_osm.sh
+++ b/installers/install_osm.sh
@@ -1,7 +1,7 @@
 #!/bin/bash
 REPOSITORY_BASE=https://osm-download.etsi.org/repository/osm/debian
 RELEASE=ReleaseFOUR
-REPOSITORY=testing
+REPOSITORY=stable
 
 add_repo() {
   REPO_CHECK="^$1"