Repository: spack/spack

Issue:
cudnn@6.0 checksum fails
```
[spackapps@lo-login-02 bin]$ spack install cudnn@6.0 ^cuda@8.0.61 %gcc@4.8.5 arch=linux-centos7-x86_64
==> cuda is already installed in /cluster/spack/apps/linux-centos7-x86_64/gcc-4.8.5/cuda-8.0.61-mxdqob5lveng3f2utljrysrx4vjp7g3m
==> Installing cudnn
==> Fetching http://developer.download.nvidia.com/compute/redist/cudnn/v6.0/cudnn-8.0-linux-x64-v6.0.tgz
######################################################################## 100.0%
==> Error: ChecksumError: md5 checksum failed for /cluster/apps/spack/var/spack/stage/cudnn-6.0-4sw354jwkals7b7dvq44fptwnwn54zra/cudnn-8.0-linux-x64-v6.0.tgz
    Expected 4aacb7acb93c5e4dfa9db814df496219 but got a08ca487f88774e39eb6b0ef6507451d
/cluster/apps/spack/lib/spack/spack/package.py:928, in do_fetch:
     896      def do_fetch(self, mirror_only=False):
     897          """
     898          Creates a stage directory and downloads the tarball for this package.
     899          Working directory will be set to the stage directory.
     900          """
     901          if not self.spec.concrete:
     902              raise ValueError("Can only fetch concrete packages.")
     903  
     904          start_time = time.time()
     905          if spack.do_checksum and self.version not in self.versions:
     906              tty.warn("There is no checksum on file to fetch %s safely." %
     907                       self.spec.format('$_$@'))
     908  
     909              # Ask the user whether to skip the checksum if we're
     910              # interactive, but just fail if non-interactive.
     911              ck_msg = "Add a checksum or use --no-checksum to skip this check."
     912              ignore_checksum = False
     913              if sys.stdout.isatty():
     914                  ignore_checksum = tty.get_yes_or_no("  Fetch anyway?",
     915                                                      default=False)
     916                  if ignore_checksum:
     917                      tty.msg("Fetching with no checksum.", ck_msg)
     918  
     919              if not ignore_checksum:
     920                  raise FetchError("Will not fetch %s" %
     921                                   self.spec.format('$_$@'), ck_msg)
     922  
     923          self.stage.fetch(mirror_only)
     924  
     925          self._fetch_time = time.time() - start_time
     926  
     927          if spack.do_checksum and self.version in self.versions:
  >> 928              self.stage.check()
     929  
     930          self.stage.cache_local()


[spackapps@lo-login-02 bin]$
```


Discussion:

Resolving patch:
diff --git a/var/spack/repos/builtin/packages/cudnn/package.py b/var/spack/repos/builtin/packages/cudnn/package.py
--- a/var/spack/repos/builtin/packages/cudnn/package.py
+++ b/var/spack/repos/builtin/packages/cudnn/package.py
@@ -32,7 +32,7 @@ class Cudnn(Package):
 
     homepage = "https://developer.nvidia.com/cudnn"
 
-    version('6.0', '4aacb7acb93c5e4dfa9db814df496219',
+    version('6.0', 'a08ca487f88774e39eb6b0ef6507451d',
             url='http://developer.download.nvidia.com/compute/redist/cudnn/v6.0/cudnn-8.0-linux-x64-v6.0.tgz')
     version('5.1', '406f4ac7f7ee8aa9e41304c143461a69',
             url='http://developer.download.nvidia.com/compute/redist/cudnn/v5.1/cudnn-8.0-linux-x64-v5.1.tgz')


Test patch: