Bug#922914: Check also on storing item

[積丹尼 Dan Jacobson]

$ XDG_UTILS_DEBUG_LEVEL=33 xdg-mime default zzzz.desktop text/html
make_default_kde: No kde runtime detected
make_default_generic zzzz.desktop text/html
Updating /home/jidanni/.config/mimeapps.list
$ cat /home/jidanni/.config/mimeapps.list
[Default Applications]
text/html=zzzz.desktop
$ XDG_UTILS_DEBUG_LEVEL=33 xdg-mime query default text/html
Checking /home/jidanni/.config/mimeapps.list
Checking /home/jidanni/.local/share/applications/mimeapps.list
Checking /home/jidanni/.local/share/applications/defaults.list and /home/jidanni/.local/share/applications/mimeinfo.cache
Checking /home/jidanni/.local/share/applications/defaults.list and /home/jidanni/.local/share/applications/mimeinfo.cache
Checking /usr/local/share//applications/defaults.list and /usr/local/share//applications/mimeinfo.cache
Checking /usr/local/share//applications/defaults.list and /usr/local/share//applications/mimeinfo.cache
Checking /usr/share//applications/defaults.list and /usr/share//applications/mimeinfo.cache
org.gnome.Epiphany.desktop
$ XDG_UTILS_DEBUG_LEVEL=33 xdg-mime query default text/html 2>&1|uniq -c
      1 Checking /home/jidanni/.config/mimeapps.list
      1 Checking /home/jidanni/.local/share/applications/mimeapps.list
      2 Checking /home/jidanni/.local/share/applications/defaults.list and /home/jidanni/.local/share/applications/mimeinfo.cache
      2 Checking /usr/local/share//applications/defaults.list and /usr/local/share//applications/mimeinfo.cache
      1 Checking /usr/share//applications/defaults.list and /usr/share//applications/mimeinfo.cache
      1 org.gnome.Epiphany.desktop

We notice: same checks messages twice. Spurious "//"s.

$ XDG_UTILS_DEBUG_LEVEL=33 xdg-mime query default text/html 2>&1|tr \  \\n|sort -u|grep ^/ |xargs grep text/html 2>&-
/home/jidanni/.config/mimeapps.list:text/html=zzzz.desktop
/home/jidanni/.local/share/applications/mimeapps.list:text/html=userapp-Aurora-OCQ17W.desktop
/home/jidanni/.local/share/applications/mimeapps.list:text/html=userapp-Aurora-OCQ17W.desktop;
/usr/share//applications/mimeinfo.cache:text/html=org.gnome.Epiphany.desktop;chromium.desktop;firefox.desktop;abiword.desktop;

$ XDG_UTILS_DEBUG_LEVEL=33 xdg-mime query default text/html
Checking /home/jidanni/.config/mimeapps.list
chromium.desktop

Conclusion:
So there is a check on if the item really exists, but it is only done on
retrieving it. Not storing it. Why not both?