cbupgrade can fail due to incorrect use of .format for older python runtime

cbupgrade has a number of print statements which will trigger failure on older (old python) systems (certainly seen on centos6)

print("message {}".format(thing)) can yield the following error

   '{}'.format(thing))

ValueError: zero length field name in format

Code was added by MB-26377 which adds the faulty prints

The older python runtime requires the {} to be indexed e.g.

print("message

".format(thing)) is safe