Fix an obscure bug causing sqlite3_close() to fail if there are virtual tables on the disconnect list when it is called.

FossilOrigin-Name: 6504aa47a8ebb13827be017c4cb4b2dc3c4c55f4

src/main.c

@@ -800,6 +800,7 @@ static void disconnectAllVtab(sqlite3 *db){
       }
     }
   }
+  sqlite3VtabUnlockList(db);
   sqlite3BtreeLeaveAll(db);
 #else
   UNUSED_PARAMETER(db);