jenkinsfile_update2head: set build server with label oem-linux

perform an update in the submodule init part

BugzID: 73574
Signed-off-by: Marc Mattmueller <marc.mattmueller@netmodule.com>

Jenkinsfile_update2head

@@ -2,7 +2,7 @@
 pipeline {
   agent {
     node {
-      label 'lxbuild4'
+      label 'oem-linux'
     }
   }
 
@@ -70,7 +70,7 @@ def printJobParameters() {
 }
 
 def prepareUpdate() {
-  sh 'git submodule init'  // init submodules used if first checkout
+  sh 'git submodule update --init'  // init submodules used if first checkout
 
   def userId = "${currentBuild.getBuildCauses()[0].userId}"
   def userName = "${currentBuild.getBuildCauses()[0].userName}"