No results displayed because special chars in Url not properly encoded

[Sugo]

System: Debian GNU/Linux 7 (wheezy)
OCS Version: 2.1.2
Client Browser: IE11 on Windows 8.1

When you filter by a custom accountinfo-field, and then in the results try to click on one of the number-links in the "count"-column, often no results are shown. I am quite sure that this happens because the "value"-part of the links is not properly url-encoded.
Sometimes it works anyway - probably depending on the browser, but f.e. if the field contains german umlaut-characters, quotes etc., no results are returned.

By manually changing non-ascii characters in a url to their corresponding encoded form and entering the url in the browsers address bar, the results page works without problems.

Also see attached screenshots, which show resulting wrong sql-queries.

Not properly encoded URL example:
https://xxxx/ocsreports/index.php?function=visu_computers&filtre=a.fields_3&value=BBZ Bruneck Hauptgebäude

Working manually corrected URL:
https://xxxx/ocsreports/index.php?function=visu_computers&filtre=a.fields_3&value=BBZ%20Bruneck%20Hauptgeb%C3%A4ude

Steps to reproduce
- Add a custom Accountinfo-Field via Administative Data icon
- Enter some info for that field, containing some special characters like german umlauts (spaces seem to work even if not encoded, at least in IE11), in at least one entry
- Click on filter icon and filter by custom field
- Hover over a number-link in "count"-column and notice that last part of url in browser's status bar is not properly encoded
- Click on number-link and notice that no info is displayed

[Philippe BEAUMONT (kapouik)]

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