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

...ngoapps/contentstore/management/commands/force_publish.py

cms/djangoapps/contentstore/tests/test_courseware_index.py

cms/djangoapps/contentstore/tests/test_import.py

cms/djangoapps/contentstore/utils.py

common/djangoapps/student/models.py

common/djangoapps/terrain/stubs/start.py

...oapps/xblock_django/management/commands/ensure_indexes.py

common/lib/capa/capa/checker.py

common/lib/capa/capa/tests/test_shuffle.py

common/lib/chem/chem/tests.py

common/lib/sandbox-packages/eia.py

common/lib/xmodule/xmodule/contentstore/utils.py

...dule/xmodule/modulestore/perf_tests/generate_asset_xml.py

...xmodule/xmodule/modulestore/perf_tests/generate_report.py

common/lib/xmodule/xmodule/modulestore/tests/factories.py

common/lib/xmodule/xmodule/modulestore/xml_importer.py

common/lib/xmodule/xmodule/tests/test_conditional.py

common/lib/xmodule/xmodule/tests/test_course_module.py

common/lib/xmodule/xmodule/tests/test_export.py

common/lib/xmodule/xmodule/tests/test_import.py