[AD] Web building make_feed problems

[Grzegorz Adam Hankiewicz <gradha@xxxxxxxxxx>]

Setting up the machine for the mirrors I got into problems running  
make_feed. It breaks down in line 54 when it tries to retrieve the  
date. The boring shell error is:

local: 89: 18:58:27+11:00: bad variable name

Something is missing escape characters. I'm running GNU Make 3.81,  
date GNU coreutils 6.10, and most likely the problem is the shell, sh  
pointing to dash 0.5.4. If I modify the script to point to /bin/bash  
instead of /bin/sh, everything seems to work.

Presumably dash is a POSIX shell, but I'm not that interested into  
filing bugs for such things, they are terribly unpleasant. Not sure if  
this is of any importance.

If it is not a problem, add .DELETE_ON_ERROR to the Makefile, so it  
won't generate bad xml if something fails in the middle.