krdb: Fix removal of Xft.dpi from Xresources
'xrdb -remove' can't remove a specific entry, it removes all entries only. So query all entries, remove "Xft.dpi" from them, and replace Xresources with the result.
'xrdb -remove' can't remove a specific entry, it removes all entries only. So query all entries, remove "Xft.dpi" from them, and replace Xresources with the result.