fixes the black market sawn illestren to actually be sawed off (shipt…

…est-ss13#3123)

before, buying the sawn illestren off the black market just gave you a
sawn illestren except it was the same size and didn't fit on belts. no
longer the case. also fixed the presawn double barrel shotgun to be the
same because it behaved the same

i bought a shitty sawed off bolt action rifle i expect to get a shitty
sawed off bolt action rifle

:cl:
fix: The black market sawed off Illestren is now actually sawed off, and
can fit on your belt
fix: The presawn double barrel shotgun can now fit on the belt like
normal sawn off double barrels
/:cl:

code/modules/projectiles/guns/ballistic/shotgun.dm

@@ -386,6 +386,7 @@ EMPTY_GUN_HELPER(shotgun/bulldog/inteq)
 	sawn_off = TRUE
 	weapon_weight = WEAPON_MEDIUM
 	w_class = WEIGHT_CLASS_NORMAL
+	slot_flags = ITEM_SLOT_BELT
 
 	wield_slowdown = 0.25
 	wield_delay = 0.3 SECONDS //OP? maybe