Invalid hex encoding in get_feedback_routes

[karlb]

mfee3_only_imbalance_fees failed on an assert involving the PFS at 2020-01-23 06:04:28.493165:

Traceback (most recent call last):
 File "/usr/local/lib/python3.7/site-packages/scenario_player/tasks/base.py", line 74, in __call__
 return self._run(*args, **kwargs)
 File "/usr/local/lib/python3.7/site-packages/scenario_player/tasks/api_base.py", line 59, in _run
 f'HTTP status code "{resp.status_code}" while fetching {url}. '
scenario_player.exceptions.legacy.RESTAPIStatusMismatchError: HTTP status code "500" while fetching https://pfs-goerli-with-fee.services-dev.raiden.network/api/v1/_debug/routes/0x5ACBaDcc1751bB6235e684AE381DA917BEFB5876/0x0D24BFe908A2C54737FD653B0698AB298B82efAe/0xa29a6992fB5c0e14Db759A54D5A10f75d8A61ac9. Expected 2..: {"message": "Internal Server Error"}

The PFS traceback is

Exception on /api/v1/_debug/routes/0x5ACBaDcc1751bB6235e684AE381DA917BEFB5876/0x0D24BFe908A2C54737FD653B0698AB298B82efAe/0xa29a6992fB5c0e14Db759A54D5A10f75d8A61ac9 [GET]                                                                                    
Traceback (most recent call last):
  File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 1832, in full_dispatch_request
    rv = self.dispatch_request()
  File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 1818, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/usr/local/lib/python3.7/site-packages/flask_restful/__init__.py", line 458, in wrapper
    resp = resource(*args, **kwargs)
  File "/usr/local/lib/python3.7/site-packages/flask/views.py", line 88, in view
    return self.dispatch_request(*args, **kwargs)
  File "/usr/local/lib/python3.7/site-packages/flask_restful/__init__.py", line 573, in dispatch_request
    resp = meth(*args, **kwargs)
  File "/services/src/pathfinding_service/api.py", line 448, in get
    for route in feedback_routes:
  File "/services/src/pathfinding_service/database.py", line 284, in get_feedback_routes
    for row in self.conn.execute(sql, filters):
  File "/services/src/raiden_libs/database.py", line 17, in convert_hex
    return int(raw, 16)
ValueError: invalid literal for int() with base 16: b'0x-0000000000000000000000000000000000000000000000000470ddb8f53a880'

Why did this not show up in sentry?