Merge lp:~cjwatson/loggerhead/py27-py35-workarounds into lp:loggerhead

[Colin Watson]

Fix py27 and py35 tox environments.

Keeping Python 2.7 and 3.5 tests working now that they're unsupported upstream and various core packages such as pip have dropped support for them is getting harder, but it's still viable with a few hacks. Loggerhead still needs to support these versions for now.

[Thiago F. Pappacena (pappacena)]

LGTM

review: Approve

[Otto Co-Pilot (otto-copilot)]

Running landing tests failed
https://jenkins.ols.canonical.com/online-services/job/loggerhead/6/

[Otto Co-Pilot (otto-copilot)]

Running landing tests failed
https://jenkins.ols.canonical.com/online-services/job/loggerhead/7/

=== modified file 'requirements.txt'
--- requirements.txt	2020-08-04 09:35:13 +0000
+++ requirements.txt	2021-04-16 21:42:30 +0000
@@ -1,3 +1,4 @@
+setuptools < 45; python_version < "3"
 Paste >= 1.6
 dulwich == 0.19.16; python_version < "3"
 dulwich; python_version >= "3"

=== modified file 'tox.ini'
--- tox.ini	2020-08-04 09:26:15 +0000
+++ tox.ini	2021-04-16 21:42:30 +0000
@@ -5,4 +5,7 @@
 [testenv]
 deps = -rrequirements.txt
 commands = brz selftest -v breezy.plugins.loggerhead --strict
-setenv = BRZ_PLUGINS_AT = loggerhead@{toxinidir}
+setenv =
+    py27,py35: VIRTUALENV_DOWNLOAD = 0
+    py27,py35: VIRTUALENV_PIP = 20.3.4
+    BRZ_PLUGINS_AT = loggerhead@{toxinidir}