Add the overwrite flag when init-ing databases

This ensures that if there is a database already in the filesystem, we
can gracefully handle creating a new one. This sometimes happens when
a user is on a self-hosted runner and neglects to clean state across
runs.

lib/codeql.js

@@ -301,6 +301,7 @@ async function getCodeQLForCmd(cmd, checkVersion) {
             await runTool(cmd, [
                 "database",
                 "init",
+                "--overwrite",
                 "--db-cluster",
                 config.dbLocation,
                 `--source-root=${sourceRoot}`,