Fix getting property from env method for upgrade pipeline

Change-Id: I2f13770e8a9dc147a808c5f18eb9e6e5bc6267f2
Related-Prod: PROD-26237 (PROD:26237)
diff --git a/upgrade-mcp-release.groovy b/upgrade-mcp-release.groovy
index b7c0468..aa8b076 100644
--- a/upgrade-mcp-release.groovy
+++ b/upgrade-mcp-release.groovy
@@ -143,10 +143,10 @@
                 // backward compatibility for 2018.11.0
                 saltMastURL = env.getProperty('SALT_MASTER_URL')
                 saltMastCreds = env.getProperty('SALT_MASTER_CREDENTIALS')
-                upgradeSaltStack = env.getProperty('UPGRADE_SALTSTACK', false).toBoolean()
-                updateClusterModel = env.getProperty('UPDATE_CLUSTER_MODEL', false).toBoolean()
-                updatePipelines = env.getProperty('UPDATE_PIPELINES', false).toBoolean()
-                updateLocalRepos = env.getProperty('UPDATE_LOCAL_REPOS', false).toBoolean()
+                upgradeSaltStack = env.getProperty('UPGRADE_SALTSTACK').toBoolean()
+                updateClusterModel = env.getProperty('UPDATE_CLUSTER_MODEL').toBoolean()
+                updatePipelines = env.getProperty('UPDATE_PIPELINES').toBoolean()
+                updateLocalRepos = env.getProperty('UPDATE_LOCAL_REPOS').toBoolean()
                 reclassSystemBranch = gitTargetMcpVersion
             }