fix elseif statement
bug #4444 fix elseif statement (MightyBranch)

This PR was submitted for the master branch but it was merged into the 2.3 branch instead (closes #4444).

Discussion
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fix elseif statement

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | all
| Fixed tickets | --

In this example of the book, the elseif block always evaluates to FALSE since $_SERVER['REQUEST_URI'] includes the query string, therefore if $uri equals to '/index.php/show' then $_GET['id'] is never set, and the list_action() is never executed.

Here I propose a fix by cleaning the query string from the URI before assigning it to $uri, using the built-in function parse_url().

Commits
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ab10529 fix elseif statement