[ostree] gnomeos: Add --skip-if-unchanged for yocto commit, also show a diff after building

[Colin Walters <walters src gnome org>]

commit 649d7c3ecfedd2b77021e00f27e86d86e87779f5
Author: Colin Walters <walters verbum org>
Date:   Fri Dec 23 07:45:13 2011 -0500

    gnomeos: Add --skip-if-unchanged for yocto commit, also show a diff after building
    
    We don't want to make new commits if nothing changed.

 gnomeos/yocto/commit-yocto-build.sh |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/gnomeos/yocto/commit-yocto-build.sh b/gnomeos/yocto/commit-yocto-build.sh
index 2778847..f622d36 100755
--- a/gnomeos/yocto/commit-yocto-build.sh
+++ b/gnomeos/yocto/commit-yocto-build.sh
@@ -37,4 +37,5 @@ BUILD_TAR=$BUILDDIR/deploy/images/gnomeos-contents-$BRANCH-qemu${ARCH}.tar.gz
 
 BUILD_TIME=$(date -r $BUILD_TAR)
 
-ostree --repo=${OSTREE_REPO} commit -s "Build from OSTree ${OSTREE_VER}" -b "gnomeos-yocto-$ARCH-$BRANCH" --tree=tar=${BUILD_TAR}
+ostree --repo=${OSTREE_REPO} commit --skip-if-unchanged -s "Build from OSTree ${OSTREE_VER}" -b "gnomeos-yocto-$ARCH-$BRANCH" --tree=tar=${BUILD_TAR}
+ostree --repo=${OSTREE_REPO} diff "gnomeos-yocto-$ARCH-$BRANCH"^ "gnomeos-yocto-$ARCH-$BRANCH"