added override power to server parameters provided on request method
fixed protocol-relative URLs
fixed too greedy replacements
bug #10549 Fixed server values in BrowserKit (fabpot)

This PR was merged into the 2.3 branch.

Discussion
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Fixed server values in BrowserKit

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #9527, #9762, #9821, #9901
| License       | MIT
| Doc PR        | n/a

Commits
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65b9810 fixed too greedy replacements
d9cf28d fixed protocol-relative URLs
289da16 added override power to server parameters provided on request method