Revert "Jenkinsfile: Enable arm64 and armhf OStree builds"

This reverts commit 473e4ddd.

Jenkinsfile

@@ -183,6 +183,11 @@ def buildOStree(architecture, type, board, debosarguments = "", production = fal
 
 def buildOStreeImage(architecture, type, board, debosarguments = "", production = false) {
 
+    if (architecture in ["arm64", "armhf"]) {
+      println "Skipping ostree image for ${architecture}"
+      return
+    }
+
     stage("${architecture} ${type} ${board} OStree image build") {
         sh(script: """\
            cd ${PIPELINE_VERSION}/${architecture}/${type}; \