Add prompt to turn on motor power supply and retry in qlatest

[pkazanzides]

The Motor Power Control test within qlatest attempts to turn on power and then verify that the motor voltage is sensed (voltage must be greater than about 11.3V). If the tester forgets to turn on the motor power supply, this test fails. It would be better to prompt the tester to turn on the power supply and retry, rather than logging a FAIL message in the log file. Reducing the number of innocuous FAIL messages will make it easier to search the files (e.g., using grep) for real failures.