Post date: Oct 27, 2015 6:27:20 PM
Click the MENU found in the top, left of the DRIVE app:
Tap the DOWNWARD facing arrow next to the username in the top, left corner:
Tap MANAGE ACCOUNTS:
Tap MANAGE:
Tap REMOVE to the right of the preferred username:
Tap REMOVE:
Tap the X to CLOSE the MANAGE window:
Thank you Sarra Smith!
http://googletiptuesday.blogspot.com/2015/10/logging-out-of-google-on-ipad.html