Title: Ensure uploaded icons are saved with their filename instead of paths
Level: 1
Component: wato
Compatible: compat
Version: 1.2.8p23
Date: 1496123348
Class: fix

Uploaded icons may be saved with their full origin path as file name 
(the location the file is stored on the client) with some browsers. This
could end up in paths like this:

C:\Users\Username\Documents\Icons\service.png will be stored in Check_MK like
~/local/share/check_mk/web/htdocs/images/icon/C:\\Users\\Username\\Documents\\Icons\\service.png

These files could not be used by the user after upload. These files are now
saved with their filename as expected.
