refactor: make Package.name consistent with other class attributes

- The 'name' attribute for packages was being set in DirectiveMeta, which
  wasn't consistent with other class properties (like fullname, etc.)

- Move it to be a class property of `PackageMeta`, and add the
  corresponding property method wrapper on `PackageBase`

lib/spack/spack/directives.py

@@ -100,11 +100,6 @@ def __init__(cls, name, bases, attr_dict):
         # that the directives are called on the class to set it up
 
         if 'spack.pkg' in cls.__module__:
-            # Package name as taken
-            # from llnl.util.lang.get_calling_module_name
-            pkg_name = cls.__module__.split('.')[-1]
-            setattr(cls, 'name', pkg_name)
-
             # Ensure the presence of the dictionaries associated
             # with the directives
             for d in DirectiveMeta._directive_names:

lib/spack/spack/package.py

@@ -229,6 +229,19 @@ def fullname(self):
         """Name of this package, including the namespace"""
         return '%s.%s' % (self.namespace, self.name)
 
+    @property
+    def name(self):
+        """The name of this package.
+
+        The name of a package is the name of its Python module, without
+        the containing module names.
+        """
+        if not hasattr(self, '_name'):
+            self._name = self.module.__name__
+            if '.' in self._name:
+                self._name = self._name[self._name.rindex('.') + 1:]
+        return self._name
+
 
 def run_before(*phases):
     """Registers a method of a package to be run before a given phase"""
@@ -472,12 +485,6 @@ def __init__(self, spec):
         # this determines how the package should be built.
         self.spec = spec
 
-        # Name of package is the name of its module, without the
-        # containing module names.
-        self.name = self.module.__name__
-        if '.' in self.name:
-            self.name = self.name[self.name.rindex('.') + 1:]
-
         # Allow custom staging paths for packages
         self.path = None
 
@@ -585,6 +592,11 @@ def fullname(self):
         """Name of this package, including namespace: namespace.name."""
         return type(self).fullname
 
+    @property
+    def name(self):
+        """Name of this package (the module without parent modules)."""
+        return type(self).name
+
     @property
     def global_license_dir(self):
         """Returns the directory where global license files for all