Remove nonexistent Python 3.5 path

[eloquence]

Description

Our virtualenv is based on Python 3.7, so this path does not in fact exist on the sd-app VM.

Note that this is an informational finding from the 2020 SecureDrop Workstation audit (TOB-SDW-013). Per the finding, the correct path already exists in sys.path at the time the incorrect path is inserted.

Test Plan

1. Build a package from this branch and install it in sd-app
2. Initialize a fresh .securedrop_client directory in sd-app
3. Observe that migrations are still correctly applied

Checklist

• I have tested these changes in the appropriate Qubes environment
• No update to the AppArmor profile is required for these changes
• No database schema changes are needed

[sssoleileraaa]

While attempting to review this, I ran into an issue on the "Checking that SHA256SUMs from mirror match signed file" step where it fails on pip-21.0.1-py3-none-any.whl. I think this is because I'm set up to use our new process for building packages with build instead of pip. Did you try rebasing onto the latest main here and attempt to build the package yourself? I'll dig in and see what I'm doing wrong here.

[sssoleileraaa]

Nevermind, I posted that comment too soon because I got tired of trying different ./scripts to sync wheels and ended up deleting the build repro and starting from scratch and it worked 🥳

[sssoleileraaa]

This works fine in Qubes