Fix dbcounter installation on Jammy

There are two problems with dbcounter installation on Jammy. The first
is straightforward. We have to use `py_modules` instead of `modules` to
specify the source file. I don't know how this works on other distros
but the docs [0] seem to clearly indicate py_modules does this.

The second issue is quite an issue and requires story time. When
pip/setuptools insteall editable installs (as is done for many of the
openstack projects) it creates an easy-install.pth file that tells the
python interpreter to add the source dirs of those repos to the python
path. Normally these paths are appended to your sys.path. Pip's isolated
build env relies on the assumption that these paths are appeneded to the
path when it santizes sys.path to create the isolated environemnt.

However, when SETUPTOOLS_SYS_PATH_TECHNIQUE is set to rewrite the paths
are not appended and are inserted in the middle. This breaks pip's
isolated build env which broke dbcounter installations. We fix this by
not setting SETUPTOOLS_SYS_PATH_TECHNIQUE to rewrite. Upstream indicates
the reason we set this half a decade ago has since been fixed properly.

The reason Jammy and nothing else breaks is that python3.10 is the first
python version to use pip's isolated build envs by default.

I've locally fiddled with a patch to pip [1] to try and fix this
behavior even when rewrite is set. I don't plan to push this upstream
but it helps to illustrate where the problem lies. If someone else would
like to upstream this feel free.

Finally this change makes the jammy platform job voting again and adds
it to the gate to ensure we don't regress again.

[0] https://docs.python.org/3/distutils/sourcedist.html#specifying-the-files-to-distribute
[1] https://paste.opendev.org/show/bqVAuhgMtVtfYupZK5J6/

Change-Id: I237f5663b0f8b060f6df130de04e17e2b1695f8a

.zuul.yaml

@@ -731,7 +731,6 @@
     parent: tempest-full-py3
     description: Ubuntu 22.04 LTS (jammy) platform test
     nodeset: openstack-single-node-jammy
-    voting: false
     timeout: 9000
     vars:
       configure_swap_size: 4096
@@ -950,6 +949,7 @@
         - devstack
         - devstack-ipv6
         - devstack-platform-centos-9-stream
+        - devstack-platform-ubuntu-jammy
         - devstack-enforce-scope
         - devstack-multinode
         - devstack-unit-tests

inc/python

@@ -194,7 +194,6 @@ function pip_install {
         https_proxy="${https_proxy:-}" \
         no_proxy="${no_proxy:-}" \
         PIP_FIND_LINKS=$PIP_FIND_LINKS \
-        SETUPTOOLS_SYS_PATH_TECHNIQUE=rewrite \
         $cmd_pip $upgrade \
         $@
     result=$?

tools/dbcounter/setup.cfg

@@ -8,7 +8,7 @@ url = http://github.com/openstack/devstack
 license = Apache
 
 [options]
-modules = dbcounter
+py_modules = dbcounter
 entry_points =
     [sqlalchemy.plugins]
     dbcounter = dbcounter:LogCursorEventsPlugin