0daced2 BREAKS Google Drive with oauth2 (works only with service_account_credentials)

[aldones]

What is the problem you are having with rclone?

Unable to perform any Google Drive Operation

What is your rclone version (eg output from rclone -V)

v1.40-132-g0daced29

Which OS you are using and how many bits (eg Windows 7, 64 bit)

RedHat Linux 7 x86_64

Which cloud storage system are you using? (eg Google Drive)

Google Drive

The command you were trying to run (eg rclone copy /tmp remote:tmp)

rclone lsd remote:
rclone sync remote:

A log from the command with the -vv flag (eg output from rclone -vv copy /tmp remote:tmp)

2018/04/27 21:49:41 DEBUG : rclone: Version "v1.40-132-g0daced29" starting with parameters ["rclone.dev" "-vv" "lsd" "aldones:"]
2018/04/27 21:49:41 DEBUG : Using config file from "/home/rodrigob/.rclone.conf"
2018/04/27 21:49:41 Failed to create file system for "aldones:": drive: failed when making oauth client: error opening service account credentials file: open : no such file or directory

Tired this both with an old .rclone entry, and with a new one created using the config option of the current version. Same problem in both cases.
I only use oauth2, and not a credential file.
Last build I tried (worked fine) was 1.40-132-gd36b80f5 (Apr 21)

[aldones]

Relevant entries from .rclone.conf (old and new, without the oauth2 data):

[aldones]
type = drive
client_id =
client_secret =
token = {"access_token":"...","token_type":"Bearer","refresh_token":"...","expiry":"2018-04-13T12:00:02.217848621-03:00"}

[roger-bueno-fdsm2]
type = google cloud storage
client_id =
client_secret =
project_number =
service_account_file =
object_acl = private
bucket_acl =
location =
storage_class =
token = {"access_token":"...","token_type":"Bearer","refresh_token":"...","expiry":"2018-04-27T22:45:35.74742743-03:00"}

[aldones]

The problem seems to have been introduced by the service_account_credentials commit (b78af51).

[ncw]

This blew up all the integration tests too!

Sloppy code review by me :-(

The fix is here

https://beta.rclone.org/v1.40-133-ga3bf6b9c/ (uploaded in 15-30 mins)