Use bash features to improve $distfiles parsing.

That means that it's not necessary anymore to use an '@' before the
extract suffix string. yay.

--HG--
extra : convert_revision : 83ce2c783cb917ef59b87eacb0565cfcff277218

templates/libungif.tmpl

@@ -2,7 +2,7 @@
 pkgname=libungif
 version=4.1.4
 distfiles="
-http://kent.dl.sourceforge.net/sourceforge/giflib/$pkgname-$version@.tar.bz2"
+http://kent.dl.sourceforge.net/sourceforge/giflib/$pkgname-$version.tar.bz2"
 build_style=gnu_configure
 configure_args="--without-x"
 configure_env="ac_cv_lib_X11_main=no"