Use built-in print() instead of print statement

In python 3 print statement is not supported, so we should use
only print() functions.

Fixes bug 1226943

Change-Id: I721e67c917ba7018401ad40ef30081883dcec420
Add logging handler for openstack_auth in the tests

Without it, log output below ERROR level can also be displayed in the
tests output.

Change-Id: I342b20fc26468a41843496f11db3e0079b50505c
Closes-Bug: #1218462
Add pagination to stack list

Implements: blueprint heat-stack-list-paging
Change-Id: I87ebd7feaeddcfe7fe76c92b075c53de7016846b
Merge "Add logging handler for openstack_auth in the tests"
Merge "Add pagination to stack list"
Merge "Use built-in print() instead of print statement"