Extension Manager suggests previous versions of Applications by default

Steps to reproduce:

1. Start XWiki 5.2
2. Login as an Admin
3. In the Applications panel on the right, click on "More applications" and then on "Install new applications"
4. Type an extension name that you know has a 5.2 stable version; for ex. use one of these: FAQ Application, JIRA Macro or IRC Bot Application
5. Hit Enter

The suggested version will be 5.1 even if the 5.2 version is compatible with your XWiki version. You can check this by installing a few 5.1 Apps, going to Extension Updater in the Administration menu and clicking on the Recompute button. All of your previously installed Apps will be listed as outdated extensions.