Changes to enable make gce to run. Added sys import so libcloud error is displayed; renamed credentials keys in template file so they work properly with gce_credentials.py. (#16607)

test/integration/credentials.template

@@ -9,9 +9,9 @@ ec2_access_key:
 ec2_secret_key:
 
 # GCE Credentials
-service_account_email:
-pem_file:
-project_id:
+gce_service_account_email:
+gce_pem_file:
+gce_project_id:
 
 # Azure Credentials
 azure_subscription_id: "{{ lookup('env', 'AZURE_SUBSCRIPTION_ID') }}"

test/integration/gce_credentials.py

@@ -1,5 +1,6 @@
 import collections
 import os
+import sys
 import yaml
 
 try: