#13 don't change file attributes when using "-f"

[Tomas Pospisek]

Rationale, from the (patched) manpage:
-f filename Use a different file to store fpm data.
Attributes of
the file are not changed - it is
assumed that the file
is being shared with other people
and therefore its
original attributes were
intentionaly set as such.

Additionaly I've renamed move_backup to make_backup since
a) this describes the function from the outside (API)
b) the function no longer only moves the file

[Tomas Pospisek]

patch