Code review comment for ~techalchemy/ubuntu-qa-tools:feature/in-memory-cookiedb

Did you actually try to use this? The sql portion of the change fails for me like so:

  $UCT/scripts/sis-changes --ppa ubuntu --pocket Proposed -r bionic --download ${HOME}/tmp/prepare-kernel-usn-6r8qbh5h/usn-bionic-linux-azure-5.3 linux-azure-5.3
  Traceback (most recent call last):
    File "/home/steve/git/ubuntu-cve-tracker/scripts/sis-changes", line 158, in <module>
      opener = lpl_common.opener_with_cookie(cve_lib.config["plb_authentication"])
    File "/home/steve/git/ubuntu-cve-tracker/scripts/lpl_common.py", line 148, in opener_with_cookie
      for line in cookie_db.iterdump():
    File "/usr/lib/python3.7/sqlite3/dump.py", line 30, in _iterdump
      schema_res = cu.execute(q)
  sqlite3.OperationalError: database is locked

which is why the shutil copy is performed in the original code.

Also, would prefer two distinct fixes as two distinct commits, please.

Thanks.