Fix (*consistentHash).Apply

[RomanZavodskikh]

consistentHash is the only load balancer algorighm which uses index of original endpoints list, that is why ctx.Route.LBEndpoints (original list) should be used there instead of ctx.LBEndpoints (list with filtered endpoints).

[MustafaSaber]

👍

[szuecs]

Do you want to add a test?

[RomanZavodskikh]

The tests are covering the bug fixed in this PR.
After fix:

$ git checkout fixConsistentHashChoice 
Already on 'fixConsistentHashChoice'
$ go test ./proxy/ -run=^TestPHCForMultipleHealthyAndOneUnhealthyEndpoints$ -count=1 
ok  	github.com/zalando/skipper/proxy	17.960s
$

Before fix:

$ git checkout HEAD^
Note: switching to 'HEAD^'.

You are in 'detached HEAD' state. You can ...
$ go test ./proxy/ -run=^TestPHCForMultipleHealthyAndOneUnhealthyEndpoints$ -count=1 
...
tp package during roundtrip: roundTrip fail injected, remote host: 127.0.0.1, request: \"GET / HTTP/1.1\", host: 127.0.0.1:41775, user agent: \"Go-http-client/1.1\""
--- FAIL: TestPHCForMultipleHealthyAndOneUnhealthyEndpoints (19.28s)
    --- FAIL: TestPHCForMultipleHealthyAndOneUnhealthyEndpoints/consistentHash (4.75s)
        healthy_endpoints_test.go:220: 
            	Error Trace:	/home/rzavodskikh/skipper/proxy/healthy_endpoints_test.go:220
            	Error:      	Max difference between 792 and 6367 allowed is 1500, but difference was -5575
            	Test:       	TestPHCForMultipleHealthyAndOneUnhealthyEndpoints/consistentHash
FAIL
FAIL	github.com/zalando/skipper/proxy	19.428s
FAIL

[AlexanderYastrebov]

👍

[RomanZavodskikh]

👍