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/perl.tmpl

@@ -1,7 +1,7 @@
 # Template build file for 'perl'.
 pkgname=perl
 version=5.10.0
-distfiles="http://www.cpan.org/src/$pkgname-$version@.tar.gz"
+distfiles="http://www.cpan.org/src/$pkgname-$version.tar.gz"
 configure_script="./Configure"
 configure_args="-Dusethreads -des -Dprefix=$XBPS_DESTDIR/$pkgname-$version/usr
  -Duselargefiles -Uusesfio -Dinstallstyle=lib/perl5 -Uinstallusrbinperl"