Bug#888798: quick boot changes to 30_os-prober prevents menu from hiding

[Mingye Wang (Artoria2e5)]

Package: grub-common
Version: 2.02-2
Version: 2.02~beta3-5
Version: 2.02~beta2-18

Since 2.02~beta2-18 Debian introduced a "quick_boot.patch" from Ubuntu, 
which allows for the bypass of boot menu. Quoting from its commit message:

 > If other operating systems are installed, then automatically unhide 
the menu.

This default is unhelpful as it overrides the manual definitions for 
GRUB_MENU_STYLE set in /etc/default/grub and provides no means of 
disabling besides manually editing the file in question, i.e. 
"/etc/grub.d/30_os-prober" or "util/grub.d/30_os-prober.in" in the 
source code. To add to the confusion, this default remains largely 
undocumented besides the commit message.

Please consider making it configurable or phasing out this default 
behavior. Such overriding decisions should be explicitly called for in 
config files like /etc/default/grub instead of riding on the top of the 
user's head.

Regards,
Artoria2e5