Change in git_functions to fetch instead of pull

Change-Id: Ibf0c0ad9b5a3e9dec93da2392ea3643cfe21fe21
Signed-off-by: garciadeblas <gerardo.garciadeblas@telefonica.com>

jenkins/common/git_functions

@@ -12,7 +12,7 @@ OSM_git_checkout() {
     if [ -d $OSM_MDG ]; then
         INFO "reusing existing workspace"
         cd $OSM_MDG
-        GIT pull --all
+        GIT fetch --all --tags
         #git checkout master  #to make sure that we are in the right branch before pulling the code
         #git pull
     else