Merge pull request #2837 from smcv/g-steal-fd

Use g_steal_fd() in preference to glnx_steal_fd()

diff --cc src/libostree/ostree-core.c
Simple merge

diff --cc src/libostree/ostree-repo-pull.c
Simple merge

diff --cc src/libostree/ostree-repo.c
Simple merge

diff --cc src/libostree/ostree-sysroot-deploy.c
Simple merge