Catch the Stage properly for Alerts (#3753)

Jenkinsfile

@@ -1,15 +1,18 @@
+def lastStage = ''
 node('node') {
   properties([disableConcurrentBuilds()])
   try {
     currentBuild.result = "SUCCESS"
 
     stage('Checkout') {
+      lastStage = env.STAGE_NAME
       checkout scm
 
       echo "Current build result: ${currentBuild.result}"
     }
     if (env.BRANCH_NAME == "master") {
         stage('Run Versions Test') {
+            lastStage = env.STAGE_NAME
             try {
               echo "Running Versions test"
 
@@ -44,6 +47,7 @@ node('node') {
     }
 
     stage('Run Rolling Upgrade Test') {
+        lastStage = env.STAGE_NAME
         try {
           echo "Running Rolling Upgrade test"
 
@@ -77,6 +81,7 @@ node('node') {
     }
 
     stage('Build Binaries') {
+      lastStage = env.STAGE_NAME
       sh 'make binaries'
 
       stash name: "storagenode-binaries", includes: "release/**/storagenode*.exe"
@@ -85,6 +90,7 @@ node('node') {
     }
 
     stage('Build Windows Installer') {
+      lastStage = env.STAGE_NAME
       node('windows') {
         checkout scm
 
@@ -99,6 +105,7 @@ node('node') {
     }
 
     stage('Sign Windows Installer') {
+      lastStage = env.STAGE_NAME
       unstash "storagenode-installer"
 
       sh 'make sign-windows-installer'
@@ -107,19 +114,23 @@ node('node') {
     }
 
     stage('Build Images') {
+      lastStage = env.STAGE_NAME
       sh 'make images'
 
       echo "Current build result: ${currentBuild.result}"
     }
 
     stage('Push Images') {
-      echo 'Push to Repo'
+      lastStage = env.STAGE_NAME
       sh 'make push-images'
+      
       echo "Current build result: ${currentBuild.result}"
     }
 
     stage('Upload') {
+      lastStage = env.STAGE_NAME
       sh 'make binaries-upload'
+      
       echo "Current build result: ${currentBuild.result}"
     }
 
@@ -129,7 +140,7 @@ node('node') {
     echo "Setting build result to FAILURE"
     currentBuild.result = "FAILURE"
 
-    slackSend color: 'danger', message: "@build-team ${env.BRANCH_NAME} build failed during stage ${env.STAGE_NAME} ${env.BUILD_URL}"
+    slackSend color: 'danger', message: "@build-team ${env.BRANCH_NAME} build failed during stage ${lastStage} ${env.BUILD_URL}"
 
     mail from: 'builds@storj.io',
       replyTo: 'builds@storj.io',