idmtool has print error on using python3

In Ubuntu 16.04, python3 is default python version, but idmtool is still using non-strict print syntax, so it won't work if we use python3, here is error information.

vagrant@odl:~$ python3 ./idmtool.py.orig
File "./idmtool.py.orig", line 143
print ''
^
SyntaxError: Missing parentheses in call to 'print'

In python3, print must use parentheses to embrace all the arguments.