Bug#841304: Lowering severity of #841292 related bugs

[Adrian Bunk <bunk@stusta.de>]

Control: severity -1 important
Control: tags -1 -stretch

I am lowering the severity of these bugs exposed by
#841292 (gcc-6: flexible array support broken).

gcc 6 has the problematic change reverted, so this shouldn't be
a problem for stretch.

This is expected to be a FTBFS with gcc >= 7,
so these will need fixing for buster.

cu
Adrian

-- 

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed