multipath: remove unnecessary fds from alias code

multipath: remove unnecessary fds from alias code

Originally, the alias code duped the bindings file fd so that a stream could
be opened on it, and then closed without closing the original fd. Later,
closing the stream was moved to the end of the function, to avoid a locking
bug.  Because of this, there isn't any point to duping the fd.  Also, since
the stream is still opened when the original fd is used, the stream
should be flushed after its done being used.

Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>