grub-2.00: remove our 40_custom

We have this in recipes-bsp/grub/grub/40_custom:

[snip]
menuentry "Linux" {
    set root=(hd0,1)
    linux /vmlinuz root=__ROOTFS__ rw __CONSOLE__ __VIDEO_MODE__ __VGA_MODE__ quiet
}
[snip]

These lines are only for initrdscripts/files/init-install.sh, the side
effect is that it would make the target's grub-mkconfig doesn't work
well since the 40_custom will be installed to /etc/grub.d/40_custom, the
grub-mkconfig will run the 40_custom, and there will always be a
'menuentry "Linux"' menu in grub.cfg no matter it is valid or not, we
can do this in init-install.sh rather than grub to fix the problem,
which is also much simpler.

We have done the related work in init-install.sh, now we need remove our own
40_custom, and use grub's own 40_custom which is the right one.

(From OE-Core rev: e5f6dc48930c8ff35df5cff3550ec2ee86641faf)

Signed-off-by: Robert Yang <liezhi.yang@windriver.com>
Signed-off-by: Roy Li <rongqing.li@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-core/initrdscripts/files/init-install-testfs.sh

@@ -167,18 +167,16 @@ umount /src_root
 # Handling of the target boot partition
 mount $bootfs /boot
 echo "Preparing boot partition..."
-if [ -f /etc/grub.d/40_custom ] ; then
+if [ -f /etc/grub.d/00_header ] ; then
     echo "Preparing custom grub2 menu..."
     GRUBCFG="/boot/grub/grub.cfg"
     mkdir -p $(dirname $GRUBCFG)
-    cp /etc/grub.d/40_custom $GRUBCFG
-    sed -i "s@__ROOTFS__@$rootfs $rootwait@g" $GRUBCFG
-    sed -i "s/__VIDEO_MODE__/$3/g" $GRUBCFG
-    sed -i "s/__VGA_MODE__/$4/g" $GRUBCFG
-    sed -i "s/__CONSOLE__/$5/g" $GRUBCFG
-    sed -i "/#/d" $GRUBCFG
-    sed -i "/exec tail/d" $GRUBCFG
-
+    cat >$GRUBCFG <<_EOF 
+menuentry "Linux" {
+    set root=(hd0,1)
+    linux /vmlinuz root=$rootfs $rootwait rw $5 $3 $4 quiet
+}
+_EOF 
     # Add the test label
     echo -ne "\nmenuentry 'test' {\nlinux /test-kernel root=$testfs rw $rootwait quiet\n}\n" >> $GRUBCFG