Add py-setuptools as dependency

With the addition of dependency types and with `py-setuptools` set as
type='build' there are more packages that need to have `py-setuptools`
added as a dependency.

This PR adds that dependency for the following packages:
- py-h5py
- py-networkx
- py-pytables
- py-scikit-image

var/spack/repos/builtin/packages/py-networkx/package.py

@@ -34,6 +34,7 @@ class PyNetworkx(Package):
     extends('python')
 
     depends_on('py-decorator', type=nolink)
+    depends_on('py-setuptools', type='build')
 
     def install(self, spec, prefix):
         python('setup.py', 'install', '--prefix=%s' % prefix)