Get Rid of nobuild, nolink, and alldeps (#2765)

* Removing the nobuild, nolink, and alldeps dependency types in favor of being explicit.
* This will help with maintenance going forward, as adding more dependency types won't affect existing declared dependencies in weird ways.
* default deptype is still `('build', 'link')`

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

@@ -35,7 +35,7 @@ class PyPyqt(Package):
     version('4.11.3', '997c3e443165a89a559e0d96b061bf70')
 
     extends('python')
-    depends_on('py-sip', type=nolink)
+    depends_on('py-sip', type=('build', 'run'))
 
     # TODO: allow qt5 when conditional deps are supported.
     # TODO: Fix version matching so that @4 works like @:4