Speed up URL tests
These tests from slapos/tests/slap.py seem to be testing the URL rewriting part of the API, but they have a side effect of actually making a connection, which fails after a long timeout.
This is two change:
- use some link local ipv6 address
- connect to example.com:80 (which will accept the connection) instead of foo.com:5000 which does not.
The total test execution time for me was reduced from 4m34.156s to 1m6.131s