py-graphviz: clean up version

testing/py-graphviz/APKBUILD

 # Contributor: Stuart Cardall <developer@it-offshore.co.uk>
 # Maintainer: Stuart Cardall <developer@it-offshore.co.uk>
 pkgname=py-graphviz
-pkgver=1.3
-_pkgver=rc2
+pkgver=1.3_rc2
+_ver=${pkgver/_/}
 pkgrel=0
 pkgdesc="Python interface to Graphviz"
 url="https://pypi.python.org/pypi/pygraphviz | http://graphviz.org/"
@@ -13,9 +13,9 @@ depends_dev=""
 makedepends="python-dev graphviz-dev"
 install=""
 subpackages="$pkgname-doc"
-source="https://github.com/pygraphviz/pygraphviz/archive/pygraphviz-$pkgver$_pkgver.tar.gz"
+source="https://github.com/pygraphviz/pygraphviz/archive/pygraphviz-$_ver.tar.gz"
 
-_builddir="$srcdir"/pygraphviz-pygraphviz-$pkgver$_pkgver
+_builddir="$srcdir"/pygraphviz-pygraphviz-$_ver
 prepare() {
 	local i
 	cd "$_builddir"