checksums: use sha256 checksums everywhere

We'd like to use a consistent checksum scheme everywhere so that we can:

    a) incorporate archive checksums into our specs and have a
       consistent hashing algorithm across all specs.

    b) index mirrors with a consistent type of checksum, and not one that
       is dependent on how spack packages are written.

- [x] convert existing md5, sha224, sha512, sha1 checksums to sha256

var/spack/repos/builtin/packages/andi/package.py

@@ -13,7 +13,7 @@ class Andi(AutotoolsPackage):
     homepage = "https://github.com/EvolBioInf/andi"
     url      = "https://github.com/EvolBioInf/andi/archive/v0.10.tar.gz"
 
-    version('0.10',    '3aaba7961798bb4aaa546baa44e469d8')
+    version('0.10',    sha256='1ff371de0b6db4080e402ded2687947dc2d6913e28626edec21dcf5149489ee8')
 
     depends_on('m4', type='build')
     depends_on('autoconf', type='build')