build: Drop linux-user-chroot around base build

Unfortunately at least on RHEL6, using --unshare-pid breaks
/proc/pid/tasks/taskid, which in turn breaks "cp -afl" inside
the chroot because coreutils "cp" is trying to set the filesystem
creation context.

Backported from ostbuild, see
https://git.gnome.org/browse/gnome-ostree/commit/?id=797fa3b71503f4269b8d1149a28f9f8914ac23a5
build: Print which component failed

Be more specific about which component failed.
buildapi: Don't reconfigure if config.status exists

Mainly this is for developers using the local: key.

EDIT: Ported to mauibuild by plfiorini