[OE-core] [PATCH 2/2] V2 Incremental image generation(Add config sample)

[Robert Yang]

Add the config sample for incremental image generation to
meta-yocto/conf/local.conf.sample.extended

[YOCTO #1651]

Signed-off-by: Robert Yang <liezhi.yang at windriver.com>
---
 meta-yocto/conf/local.conf.sample.extended |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/meta-yocto/conf/local.conf.sample.extended b/meta-yocto/conf/local.conf.sample.extended
index 7c26572..64efaa0 100644
--- a/meta-yocto/conf/local.conf.sample.extended
+++ b/meta-yocto/conf/local.conf.sample.extended
@@ -123,3 +123,10 @@
 # The following is a list of classes to import to use in the generation of images
 # currently an example class is image_types_uboot
 # IMAGE_CLASSES = " image_types_uboot"
+
+# Incremental image generation(only for rpm based rootfs currently), the rootfs
+# would be totally removed and re-created in the second generation by default,
+# but with INC_IMAGE_GEN = "1", the rootfs would be kept, and will do
+# update(remove/add some pkgs) on it.
+# NOTE: This is not suggested when you want to create a productive rootfs
+#INC_IMAGE_GEN = "1"
-- 
1.7.4.1