mke2fs: modify the fallback path for copying data

mke2fs: modify the fallback path for copying data

Right now we jump to the end as soon as we've found a method that works.
This is a reasonable approach because it's the last operation in the
function, but soon it won't be.  Switch to a logically-equivalent
alternative approach: keep trying until we find the approach that works,
dropping the `goto out`.  Now we can add code after this.

Signed-off-by: Allison Karlitskaya <allison.karlitskaya@redhat.com>