Fix images not being modifiable by mender-artifact in thud and later.

Changelog: Title

The problem is that the "metadata_csum" feature is very recent, and in
fact even the version shipped in poky (1.44.3) doesn't support it
(both fsck.ext4 and tune2fs refuse to handle it). Why they turned it
on in the first place is a mystery to me. In any case it should be
safe to turn off for our images, so that debugfs (and hence
mender-artifact) is able to handle the image.

If anyone requires this feature, it can be flipped on again on the
built image by a recent version of e2fsprogs/tune2fs.

Signed-off-by: Kristian Amlie <kristian.amlie@northern.tech>

meta-mender-core/recipes-devtools/e2fsprogs/e2fsprogs_1.44.%.bbappend

@@ -0,0 +1,2 @@
+FILESEXTRAPATHS_prepend := "${THISDIR}/patches:"
+SRC_URI_append = " file://0001-Do-not-use-metadata_csum-feature-on-ext4-by-default.patch"

meta-mender-core/recipes-devtools/e2fsprogs/patches/0001-Do-not-use-metadata_csum-feature-on-ext4-by-default.patch

@@ -0,0 +1,28 @@
+From 24bc347ed1303d649347c1dc2f813ab0c29f9f99 Mon Sep 17 00:00:00 2001
+From: Kristian Amlie <kristian.amlie@northern.tech>
+Date: Fri, 30 Nov 2018 09:06:17 +0000
+Subject: [PATCH 1/1] Do not use metadata_csum feature on ext4 by default.
+
+Even very recent versions of e2fsprogs (1.44.3) don't support it.
+
+Signed-off-by: Kristian Amlie <kristian.amlie@northern.tech>
+---
+ misc/mke2fs.conf.in | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/misc/mke2fs.conf.in b/misc/mke2fs.conf.in
+index 25105b3..df643ed 100644
+--- a/misc/mke2fs.conf.in
++++ b/misc/mke2fs.conf.in
+@@ -11,7 +11,7 @@
+ 		features = has_journal
+ 	}
+ 	ext4 = {
+-		features = has_journal,extent,huge_file,flex_bg,metadata_csum,dir_nlink,extra_isize
++		features = has_journal,extent,huge_file,flex_bg,dir_nlink,extra_isize
+ 		inode_size = 256
+ 		auto_64-bit_support = 1
+ 	}
+-- 
+2.7.4
+