[OE-core] fix '[[: not found' error message using dash

[Vincent Génieux]

This is a fix for https://bugzilla.yoctoproject.org/show_bug.cgi?id=7112
bash specific syntax '[[ test ]]' replaced with '[ test ]'.

Signed-off-by: Vincent Génieux <vincent2014 at startigen.fr>
---
 meta/classes/kernel.bbclass |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/meta/classes/kernel.bbclass b/meta/classes/kernel.bbclass
index 70ed95b..2a6ec34 100644
--- a/meta/classes/kernel.bbclass
+++ b/meta/classes/kernel.bbclass
@@ -403,7 +403,7 @@ do_strip() {
 			  gawk '{print $1}'`
 
 		for str in ${KERNEL_IMAGE_STRIP_EXTRA_SECTIONS}; do {
-			if [[ "$headers" != *"$str"* ]]; then
+			if [ "$headers" != *"$str"* ]; then
 				bbwarn "Section not found: $str";
 			fi
 
-- 
1.7.10.4