Use print() function in both Python 2 and Python 3

[cclauss]

Legacy print statements are syntax errors in Python 3 but print() function works as expected in both Python 2 and Python 3. Also fixed some undefined names.

Four undefined names remain...

$ flake8 . --count --show-source --statistics --select=E9,F63,F7,F82

./samples/coordinate/coordinate.py:60:13: F821 undefined name 'build'
  service = build('coordinate', 'v1', http=http)
            ^
./samples/coordinate/coordinate.py:60:44: F821 undefined name 'http'
  service = build('coordinate', 'v1', http=http)
                                           ^
./samples/coordinate/coordinate.py:64:46: F821 undefined name 'FLAGS'
    jobs_result = service.jobs().list(teamId=FLAGS.teamId).execute(http=http)
                                             ^
./samples/coordinate/coordinate.py:64:73: F821 undefined name 'http'
    jobs_result = service.jobs().list(teamId=FLAGS.teamId).execute(http=http)
                                                                        ^
4     F821 undefined name 'build'
4

[busunkim96]

Thank you @cclauss!

[tseaver]

This change loses the re-bound exception below, which means it loses information about the actual cause.