testexport: Fix to work as an image class

The class is mainly an image based class but one recipe does need to look
at values shared with the class and isn't an image. Move this to a conf
file instead, avoiding the need to pollute all recipes globally.

(From OE-Core rev: ed4238487c81b3580e83c257b50745a832a6e717)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/classes/testexport.bbclass

@@ -23,10 +23,9 @@ TEST_TARGET ?= "simpleremote"
 TEST_TARGET_IP ?= ""
 TEST_SERVER_IP ?= ""
 
-TEST_EXPORT_SDK_PACKAGES ?= ""
+require conf/testexport.conf
+
 TEST_EXPORT_SDK_ENABLED ?= "0"
-TEST_EXPORT_SDK_NAME ?= "testexport-tools-nativesdk"
-TEST_EXPORT_SDK_DIR ?= "sdk"
 
 TEST_EXPORT_DEPENDS = ""
 TEST_EXPORT_DEPENDS += "${@bb.utils.contains('IMAGE_PKGTYPE', 'rpm', 'cpio-native:do_populate_sysroot', '', d)}"

meta/conf/testexport.conf

@@ -0,0 +1,3 @@
+TEST_EXPORT_SDK_PACKAGES ?= ""
+TEST_EXPORT_SDK_DIR ?= "sdk"
+TEST_EXPORT_SDK_NAME ?= "testexport-tools-nativesdk"

meta/recipes-core/meta/testexport-tarball.bb

@@ -4,7 +4,7 @@ DESCRIPTION = "SDK type target for standalone tarball containing packages define
 SUMMARY = "Standalone tarball for test systems with missing software"
 LICENSE = "MIT"
 
-TEST_EXPORT_SDK_PACKAGES ??= ""
+require conf/testexport.conf
 
 TOOLCHAIN_TARGET_TASK ?= ""