libc/eglibc: fix downloading

Since Subversion 1.6.13 was released, it is no longer possible
to checkout/export to the current working directory using '.'
(eg. "svn co bla://blabla/foo/bar ." no longer extracts the content
of bar into ./ but into ./bar).

Fix this by luring Subversion to extract into "$(pwd)", which has
the advantage of working both with all known versions so far.

At the same time, remove the useless redirection.
(transplanted from 42cc9bd0db7ea6d690efab40742881414f7c1277)

# Options specific to crosstool-NG acting as a backend

config IS_A_BACKEND

    string

    option env="CT_IS_A_BACKEND"

config BACKEND

    bool

    default y if IS_A_BACKEND =  "y" || IS_A_BACKEND =  "Y"

    default n if IS_A_BACKEND != "y" && IS_A_BACKEND != "Y"

config BACKEND_ARCH

    string

    option env="CT_BACKEND_ARCH"

config BACKEND_KERNEL

    string

    option env="CT_BACKEND_KERNEL"

config BACKEND_LIBC

    string

    option env="CT_BACKEND_LIBC"