fix: the web service starts once libpq can be found.

debian-package/src/usr/lib/vpn-router/web

@@ -30,11 +30,10 @@ default the address the service listens on, is the last entry of its X-Forwarded
 Docker is installed, and the state of site-to-site, road-warrior (IPsec P2S), OpenVPN and
 WireGuard. No configuration data, key or address is shown.
 
-The service first initializes, without listening: it loads the PostgreSQL driver
-(vpnrouter_auth.driver; psycopg finds libpq through the linker cache, which the package manager
-refreshes only at the end of an installation), then it makes the signing key and the refresh
+The service first initializes, without listening: it makes the signing key and the refresh
 tokens' database (vpnrouter_auth), retrying every INIT_RETRY_SECONDS until both are ready and
-logging each failure. Then it listens.
+logging each failure. Then it listens. Its unit starts it only once wait-for-libpq has found libpq
+in the linker cache, where psycopg looks it up.
 
 The service needs nothing else to start and does not end on its own. Every DISCOVERY_SECONDS it
 works out the internal address from /etc/vpn-router/vpn-router.json as general.mode directs,
@@ -697,13 +696,11 @@ def log(message):
 
 
 def initialize():
-    """Load the PostgreSQL driver, make the signing key and the refresh tokens' database, retrying every INIT_RETRY_SECONDS until all are ready."""
+    """Make the signing key and the refresh tokens' database, retrying every INIT_RETRY_SECONDS until both are ready."""
     reported = None
     while True:
-        phase = 'loading the PostgreSQL driver'
+        phase = 'reading the configuration'
         try:
-            vpnrouter_auth.driver()
-            phase = 'reading the configuration'
             cfg = vpnrouter.load_config()
             phase = 'making the signing key'
             vpnrouter_auth.ensure_key()