Partly revert r18363, "Minor windows version updates: Newer gmp, newer slib."

The newest build doesn't even start the gnucash main window (only the
splash screen). Hence, we revert the changed slib version because this might
affect that behaviour.

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@18368 57a11ea4-9604-0410-9ed3-97b8803252fd

packaging/win32/defaults.sh

@@ -138,7 +138,7 @@ set_default GMP_ABI 32
 set_default GMP_DIR $GLOBAL_DIR\\gmp
 
 set_default GUILE_URL "http://ftp.gnu.org/pub/gnu/guile/guile-1.6.8.tar.gz"
-set_default SLIB_URL "http://groups.csail.mit.edu/mac/ftpdir/scm/slib-3b2.zip"
+set_default SLIB_URL "http://swiss.csail.mit.edu/ftpdir/scm/OLD/slib3a3.zip"
 set_default GUILE_DIR $GLOBAL_DIR\\guile
 
 set_default OPENSSL_URL "http://www.openssl.org/source/openssl-0.9.8j.tar.gz"