update mongo password

Author: Bryan Kendall

ansible/gamma-hosts/variables

@@ -6,7 +6,7 @@ api_github_client_secret=ad4f8527ae98d7eea15a32ee5abbead5c9a25abc
 api_github_deploy_keys_bucket=runnable.deploykeys.production-gamma
 api_hello_runnable_github_token=88ddc423c2312d02a8bbcaad76dd4c374a30e4af
 api_mixpanel_app_id=c41affa4b08818443365c526cbb51606
-api_mongo_auth=api:oW4c7x9Wiv28oiNBy2Bc
+api_mongo_auth=api:3f5210b8-8fe3-11e5-8e62-07b6eff19ecb
 api_mongo_database=gamma
 api_mongo_replset_name=gamma-rs0
 api_neo4j_auth=neo4j:oqGlRV1KTpaqbHDkdlJz