make HTTP MOVED messages also work in ffmpeg (302 is essentially the same as 303).

patch by "Ronald S. Bultje" % rbultje A ronald P bitfreak P net%
original thread:
Date: Mar 4, 2007 1:21 AM
Subject: [Ffmpeg-devel] http move

Originally committed as revision 8219 to svn://svn.ffmpeg.org/ffmpeg/trunk