Replace FQDN for `TestLookupSRV`

[raspbeguy]

Tests are failing because it tried to resolve _xmpp-server._tcp.google.com but this resolve to anything now. Please choose another FQDN for this.

FAIL: template_funcs_test.go:46: FunctionTestSuite.TestLookupSRV

template_funcs_test.go:82:
    t.Error(err)
... Error: lookup _xmpp-server._tcp.google.com on 192.168.0.1:53: no such host

template_funcs_test.go:84:
    t.Check(srv, DeepEquals, expected)
... obtained []*net.SRV = []*net.SRV(nil)
... expected []*net.SRV = []*net.SRV{(*net.SRV)(0xc000012bd0), (*net.SRV)(0xc000012be8), (*net.SRV)(0xc000012c00), (*net.SRV)(0xc000012c18), (*net.SRV)(0xc000012c30)}
... Difference:
...     []*net.SRV[0] != []*net.SRV[5]