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/adept-utils/package.py

@@ -12,8 +12,8 @@ class AdeptUtils(CMakePackage):
     homepage = "https://github.com/llnl/adept-utils"
     url      = "https://github.com/llnl/adept-utils/archive/v1.0.tar.gz"
 
-    version('1.0.1', '731a310717adcb004d9d195130efee7d')
-    version('1.0',   '5c6cd9badce56c945ac8551e34804397')
+    version('1.0.1', sha256='259f777aeb368ede3583d3617bb779f0fde778319bf2122fdd216bdf223c015e')
+    version('1.0',   sha256='fed29366c9bcf5f3799220ae3b351d2cb338e2aa42133d61584ea650aa8d6ff7')
 
     depends_on('boost')
     depends_on('mpi')