Short answer: I agree completely with your last paragraph, there's no electrolysis. Long answer: er, technically, yes, there's electrolysis.
There will be electrolysis, but it will be negligible and probably not even measurable. When you pass current through the pipe, voltage is not even across the pipe. Voltage will be higher at the bonding point than at the ground due to voltage drop through the pipe. This creates an electromotive potential that will send small amounts of current through the (poorly conducting) electrolyte, and set up likely immesurable amounts of electrolysis through the pipe. Any oxygen created will eventually react with the pipe, and you'd get a small buildup of hydrogen gas over time.
