linux-yocto: fix unapplied patch error message

When patches fail to apply, the status of all pending patches should
be exported to the logs and to the user. Currently, a missing export
of GUILT_BASE makes it look more like an internal error, than a 'normal'
patch failure:

    | [ERROR] unable to complete push
    | pending patches are:
    | Patches directory doesn't exist, try guilt-init

With this variable exported, we have this:

  | [INFO] validating against known patches  (qemux86-standard-meta)
  | error: patch failed: Makefile:2
  | error: Makefile: patch does not apply
  | To force apply this patch, use 'guilt push -f'
  | [ERROR] unable to complete push
  | pending patches are:
  | links/files/0002-makefile-patch.patch

(From OE-Core rev: b2b2512cbc4196fa0f814be3677517dab30e5b52)

Signed-off-by: Bruce Ashfield <bruce.ashfield@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/classes/kernel-yocto.bbclass

@@ -97,7 +97,8 @@ do_patch() {
 	# executes and modifies the source tree as required
 	patchme ${KMACHINE}
 	if [ $? -ne 0 ]; then
-		echo "ERROR. Could not apply updates for ${KMACHINE}"
+		echo "ERROR. Could not apply patches for ${KMACHINE}."
+		echo "       Patch failures can be resolved in the devshell (bitbake -c devshell ${PN})"
 		exit 1
 	fi
 

meta/recipes-kernel/kern-tools/kern-tools-native_git.bb

@@ -4,7 +4,7 @@ LIC_FILES_CHKSUM = "file://git/tools/kgit;beginline=5;endline=9;md5=d8d1d729a70c
 
 DEPENDS = "git-native guilt-native"
 
-SRCREV = "c82d67d0cf17bc3b499f19667690c56bd00d3ddc"
+SRCREV = "6e92eca3bd30d73222dfeaae6d2d1d9764a5a3f8"
 PR = "r12"
 PV = "0.1+git${SRCPV}"