Bug#930291: hplip-gui unable to see hp plugin and fails to add printer

[Timothy L. Miller]

Package: hplip-gui
Version: 3.18.12+dfsg0-2

When launching hplip-gui to add a printer, it successfully detects 
printer, launches plugin installer, installs plugin, then says that it 
cannot install printer because it requires a plugin (that was installed 
on prior step).  Does same thing if you run hp-plugin from a CLI to 
install plugin (pluin install succeeds, printer install fails due to 
needing plugin).

Linux duskblade 4.19.0-5-amd64 #1 SMP Debian 4.19.37-3 (2019-05-15) 
x86_64 GNU/Linux