db: Create var/lib/rpm -> ../../usr/share/rpm in tempdir
db: Create var/lib/rpm -> ../../usr/share/rpm in tempdir

hawkey and libsolv are both patched to look in `usr/share/rpm` if the
db can't be found in `/var/lib/rpm`.  However, librpm itself isn't.
One *can* override it with a macro...which is process global.  Yuck.
Needs fixing.

Anyways, we can just make a symlink.  That's a lot easier than writing
a patch for librpm and waiting a billion years to be able to use it
everywhere we care about.

This will help unify the librpm tempdir code with the hawkey tempdir
code.

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