[gnome-continuous-yocto/gnomeostree-3.28-rocko: 5847/8267] image.bbclass: Set ROOTFS_RO_UNNEEDED correctly

[Emmanuele Bassi <ebassi src gnome org>]

commit 6ea5de4433a3040070582496ca16c17019cee233
Author: David Vincent <freesilicon gmail com>
Date:   Wed Apr 26 11:30:39 2017 +0200

    image.bbclass: Set ROOTFS_RO_UNNEEDED correctly
    
    Use a weak assignment for ROOTFS_RO_UNNEEDED to let users define their
    own list overriding defaults.
    
    (From OE-Core rev: aeec0b2ccdf8566dd07961f8c4c44fcff13b70c8)
    
    Signed-off-by: David Vincent <freesilicon gmail com>
    Signed-off-by: Ross Burton <ross burton intel com>
    Signed-off-by: Richard Purdie <richard purdie linuxfoundation org>

 meta/classes/image.bbclass |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/meta/classes/image.bbclass b/meta/classes/image.bbclass
index 405fd73..58cd608 100644
--- a/meta/classes/image.bbclass
+++ b/meta/classes/image.bbclass
@@ -33,7 +33,7 @@ ROOTFS_BOOTSTRAP_INSTALL = "run-postinsts"
 
 # These packages will be removed from a read-only rootfs after all other
 # packages have been installed
-ROOTFS_RO_UNNEEDED = "update-rc.d base-passwd shadow ${VIRTUAL-RUNTIME_update-alternatives} 
${ROOTFS_BOOTSTRAP_INSTALL}"
+ROOTFS_RO_UNNEEDED ??= "update-rc.d base-passwd shadow ${VIRTUAL-RUNTIME_update-alternatives} 
${ROOTFS_BOOTSTRAP_INSTALL}"
 
 # packages to install from features
 FEATURE_INSTALL = "${@' '.join(oe.packagegroup.required_packages(oe.data.typed_value('IMAGE_FEATURES', d), 
d))}"