jobs/build: gate all rerun logic on uploading

We only actually run the jobs when `uploading` is set. So it seems wrong
to update the build description. In fact, let's not even waste time
looking for missing arches or reading build metadata.

Patch best viewed with whitespace ignored.

jobs/build.Jenkinsfile

@@ -265,15 +265,16 @@ lock(resource: "build-${params.STREAM}") {
  // Nothing changed since the latest build. Check if it's missing
  // some arches and retrigger `build-arch` only for the missing
  // arches, and the follow-up `release` job. Match the exact src
- // config commit that was used.
- def builds = readJSON file: "builds/builds.json"
- assert buildID == builds.builds[0].id
- def missing_arches = additional_arches - builds.builds[0].arches
- if (missing_arches) {
- def meta = readJSON(text: shwrapCapture("cosa meta --build=${buildID} --dump"))
- def rev = meta["coreos-assembler.config-gitrev"]
- currentBuild.description = "${build_description} 🔨 ${buildID}"
- if (uploading) {
+ // config commit that was used. Skip if not uploading since it's
+ // required for multi-arch.
+ if (uploading) {
+ def builds = readJSON file: "builds/builds.json"
+ assert buildID == builds.builds[0].id
+ def missing_arches = additional_arches - builds.builds[0].arches
+ if (missing_arches) {
+ def meta = readJSON(text: shwrapCapture("cosa meta --build=${buildID} --dump"))
+ def rev = meta["coreos-assembler.config-gitrev"]
+ currentBuild.description = "${build_description} 🔨 ${buildID}"
  // Run the mArch jobs and wait. We wait here because if they fail
  // we don't want to bother running the release job again since the
  // goal is to get a complete build.