Document entries pointing to unavailable network shares freeze
the application menu, so avoid calling QT_LSTAT (lstat64())
three times for each list item and reading the first 16k of
each document when showing the recent documents list in application
menu.
The current behaviour of accessing each document in the list
just by browsing the application menu is inacceptable in large
enterprise environments where thousands of users work
with documents located on mounted network shares. This induces
additional load on filers and network, slows down working
with the menu and makes its functioning dependent on network
and remote filesystems.