Revert "gawk: bump to version 4.0.2"

This reverts commit 6b307de4 (version part).

Fixes http://autobuild.buildroot.org/results/46828cef48bc1267583ba8174c0e8ee993fac865



As discussed on the list, let's revert this for the 2013.02 release
and then bring it up wiith gawk upstream / try to fix for 2013.05+

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>