exec: Clean up fall back when -mem-path allocation fails

exec: Clean up fall back when -mem-path allocation fails

With -mem-path, qemu_ram_alloc_from_ptr() first tries to allocate
accordingly, but when it fails, it falls back to normal allocation.

The fall back allocation code used to be effectively identical to the
"-mem-path not given" code, until it started to diverge in commit
432d268.  I believe the code still works, but clean it up anyway: drop
the special fall back allocation code, and fall back to the ordinary
"-mem-path not given" code instead.

Reviewed-by: Paolo Bonzini <[email protected]>
Signed-off-by: Markus Armbruster <[email protected]>
Acked-by: Laszlo Ersek <[email protected]>
Acked-by: Stefano Stabellini <[email protected]>
Message-id: 1375276272[email protected]
Signed-off-by: Anthony Liguori <[email protected]>