unit test for #1679
do not cache and re-use imm filenodes in nodemaker

fixes #1679
Add comment explaining fix to #1679. refs #1679

Signed-off-by: David-Sarah Hopwood <david-sarah@jacaranda.org>
test_web.py: fix test_GET_DIRECTORY_html_filenode_encoding for Twisted==12.3.0. fixes #1922

twisted.web.html.escape was used to produce html-encoded string (to then look
it up in "value" attribute), but behavior of that function has changed between
Twisted 12.2.0 (simple custom implementation) and 12.3.0 (imported from stdlib
cgi module).
Merge trunk into 1909-cloud-openstack
Merge branch '1909-cloud-openstack' into cloud-google-storage
Refactor useful functionality out of OpenStackContainer and into utility class.
googlestorage_container.py: Implement GET object.