Convert to using python format to align and interpolate values to
ensure the correct output on python 2 & 3 when dealing with unicode and
str.
Interpolating strings using encode into '%s' and subsequently
interpolating the results into a second string results in the output
printing embedded byte strings on python 3.
$ git-review -l
b'226894' b'master' b'Add pem key parameter (WIP)'
b'199225' b'master' b'support urls as change-id input
Which occurs because after converting a string to unicode bytes, it was
then interpolated using '%s'.
Switching to using '.format()' method takes care of converting the
output to the correct string format for python 2 & 3 automatically.
Change-Id: Ia962d18bda34e0244fb05636a7be263045ecb256
efb5126e67