[NC-1946] fix slack notifications for master build status (#335)

Jenkinsfile

@@ -18,6 +18,7 @@ if (env.BRANCH_NAME == "master") {
     ])
 }
 
+try {
     stage('Pantheon tests') {
         parallel javaTests: {
             node {
@@ -86,21 +87,32 @@ stage('Pantheon tests') {
             }
         }
     }
-
+} catch (e) {
+    currentBuild.result = 'FAILURE'
+} finally {
     // If we're on master and it failed, notify slack
     if (env.BRANCH_NAME == "master") {
-    if (currentBuild.result != 'SUCCESSFUL') {
+        def currentResult = currentBuild.result ?: 'SUCCESS'
         def channel = '#priv-pegasys-prod-dev'
-        if (currentBuild.result == 'FAILURE') {
+        if (currentResult == 'SUCCESS') {
+            def previousResult = currentBuild.previousBuild?.result
+            if (previousResult != null && (previousResult == 'FAILURE' || previousResult == 'UNSTABLE')) {
+                slackSend(
+                    color: 'good',
+                    message: "Pantheon branch ${env.BRANCH_NAME} build is back to HEALTHY.\nBuild Number: #${env.BUILD_NUMBER}\n${env.BUILD_URL}",
+                    channel: channel
+                )
+            }
+        } else if (currentBuild.result == 'FAILURE') {
             slackSend(
                 color: 'danger',
-                msg: "Pantheon master branch build is FAILING.\nBuild Number: #${env.BUILD_NUMBER}\n${env.BUILD_URL}",
+                message: "Pantheon branch ${env.BRANCH_NAME} build is FAILING.\nBuild Number: #${env.BUILD_NUMBER}\n${env.BUILD_URL}",
                 channel: channel
             )
         } else if (currentBuild.result == 'UNSTABLE') {
             slackSend(
                 color: 'warning',
-                msg: "Pantheon master branch build is UNSTABLE.\nBuild Number: #${env.BUILD_NUMBER}\n${env.BUILD_URL}",
+                message: "Pantheon branch ${env.BRANCH_NAME} build is UNSTABLE.\nBuild Number: #${env.BUILD_NUMBER}\n${env.BUILD_URL}",
                 channel: channel
             )
         }