[OE-core] [PATCH] testexport-tarball: Add default value for TEST_EXPORT_SDK_PACKAGES

[Richard Purdie]

Otherwise we see parsing failures in the default configuration:

'''
Nothing RPROVIDES '${TEST_EXPORT_SDK_PACKAGES}' (but
/media/build1/poky/meta/recipes-core/meta/testexport-tarball.bb
RDEPENDS on or otherwise requires it)
'''

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

diff --git a/meta/recipes-core/meta/testexport-tarball.bb b/meta/recipes-core/meta/testexport-tarball.bb
index 951d3be..d9861c4 100644
--- a/meta/recipes-core/meta/testexport-tarball.bb
+++ b/meta/recipes-core/meta/testexport-tarball.bb
@@ -6,6 +6,8 @@ LICENSE = "MIT"
 LIC_FILES_CHKSUM = "file://${COREBASE}/LICENSE;md5=4d92cd373abda3937c2bc47fbc49d690 \
                     file://${COREBASE}/meta/COPYING.MIT;md5=3da9cfbcb788c80a0384361b4de20420"
 
+TEST_EXPORT_SDK_PACKAGES ??= ""
+
 TOOLCHAIN_TARGET_TASK ?= ""
 
 TOOLCHAIN_HOST_TASK ?= "${TEST_EXPORT_SDK_PACKAGES}"