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/mpfr.tmpl

@@ -1,7 +1,7 @@
 # Template build file for 'mpfr'
 pkgname=mpfr
 version=2.3.2
-distfiles="http://www.mpfr.org/mpfr-current/$pkgname-$version@.tar.bz2"
+distfiles="http://www.mpfr.org/mpfr-current/$pkgname-$version.tar.bz2"
 build_style=gnu_configure
 short_desc="Library for multiple-precision floating-point computations"
 maintainer="Juan RP <xtraeme@gmail.com>"