Fix Clock fault condition

[bschulz1701]

Currently when no clock battery is installed, the message printed is

Clock:  PASS, BAD TIME
 FAIL

This triggers both an OBError and a TimeError, fix such that if the clock does not increment (which will correctly cause an OBError), then this invalidates a TimeError and the resurned result should simply be

Clock: FAIL

Triggering just an OBError, not a TimeError since this (while technically correct) is confusing and can give the illusion from light states that the clock is not the problem

[awickert]

Just tested now after removing the CR1220 battery. Output:

Timestamp = 2000/01/01 00:00:00
I2C:  Fail
   Fail At: 42
Clock:  PASS, BAD TIME
SD: PASS
Bat = 2.77V	0.00%
Temp = 23.66C
Pressure = 997.17 mBar
RH = 20.30%

The I2C fail is for Project Haar; not related to the problem here, I think.