`proxy.config.http.number_of_redirections` not being honoured.

[brbzull0]

While looking at #2742 I found that the proxy.config.http.number_of_redirections seems not to be working as expected.
In my configuration I set this config variable to 1 expecting TS to just follow the 302 once, but in my scenario where I have 2 302 being returned by different origin server I can see that TS follows it twice.

Sequence:

1 - client -> ATS  GET foo.test/
2 - ATS -> origin GET /
3 - origin -> ATS 302 bar.test/ ( ATS will follow )
4 - ATS -> GET bar.test/ (1 redirect)
5 - origin -> ATS  302 kau.test/  (again another 302, but as number_of_redirections was set to 1, then no more redirects should happen, but...)
6 - ATS -> kau.test/
...

in #6 ATS is following the 302 when it should not as proxy.config.http.number_of_redirections was set to 1.

Please check the logs for more detail: TS-LOG

After a quick look at the code, it seems that we may be comparing the counting wrongly in several places.

If more details on the scenario is needed, please check this commit on my local branch, this commit correspond to WIP test

Using latest from master branch.