status: Consistently use malloc'd() memory for status
status: Consistently use malloc'd() memory for status

This crashed when "atomic status" on an origin that didn't have a
refspec, which happened via my new atomic-pkglayer demo script.

mdshuai/rpm-ostree,giuseppe/rpm-ostree,mdshuai/rpm-ostree,giuseppe/rpm-ostree,tmp-user/rpm-ostree,tmp-user/rpm-ostree,giuseppe/rpm-ostree,tmp-user/rpm-ostree,mdshuai/rpm-ostree,giuseppe/rpm-ostree,tmp-user/rpm-ostree,mdshuai/rpm-ostree