Remove PluginBase/NodePluginBase class

A majority of the "plugins" aren't implementing the plugin class.
Clearly we need some refactoring of the ideas here.  Remove for
simplicity.

Change-Id: If399a371b171f4fd17cfa5856fe55daca4c86e60

diskimage_builder/block_device/level0/localloop.py

@@ -18,7 +18,6 @@ import subprocess
 
 from diskimage_builder.block_device.blockdevice import \
     BlockDeviceSetupException
-from diskimage_builder.block_device.plugin_base import NodePluginBase
 from diskimage_builder.block_device.tree_config import TreeConfig
 from diskimage_builder.block_device.utils import parse_abs_size_spec
 from diskimage_builder.graph.digraph import Digraph
@@ -27,7 +26,7 @@ from diskimage_builder.graph.digraph import Digraph
 logger = logging.getLogger(__name__)
 
 
-class LocalLoop(NodePluginBase):
+class LocalLoop(Digraph.Node):
     """Level0: Local loop image device handling.
 
     This class handles local loop devices that can be used
@@ -56,6 +55,10 @@ class LocalLoop(NodePluginBase):
         """Because this is created without base, there are no edges."""
         pass
 
+    def insert_nodes(self, dg):
+        """Adds self as a node to the given digraph"""
+        dg.add_node(self)
+
     @staticmethod
     def image_create(filename, size):
         logger.info("Create image file [%s]" % filename)

diskimage_builder/block_device/level1/partitioning.py

@@ -20,7 +20,6 @@ from subprocess import CalledProcessError
 from diskimage_builder.block_device.blockdevice import \
     BlockDeviceSetupException
 from diskimage_builder.block_device.level1.mbr import MBR
-from diskimage_builder.block_device.plugin_base import PluginBase
 from diskimage_builder.block_device.tree_config import TreeConfig
 from diskimage_builder.block_device.utils import exec_sudo
 from diskimage_builder.block_device.utils import parse_abs_size_spec
@@ -136,7 +135,7 @@ class PartitioningTreeConfig(object):
         logger.debug("finished new [%s] complete [%s]" % (nconfig, dconfig))
 
 
-class Partitioning(PluginBase):
+class Partitioning(Digraph.Node):
 
     tree_config = PartitioningTreeConfig()
 

diskimage_builder/block_device/plugin_base.py

@@ -1,52 +0,0 @@
-# Copyright 2017 Andreas Florath (andreas@florath.net)
-#
-# Licensed under the Apache License, Version 2.0 (the "License"); you may
-# not use this file except in compliance with the License. You may obtain
-# a copy of the License at
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
-# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
-# License for the specific language governing permissions and limitations
-# under the License.
-
-import abc
-import six
-
-from diskimage_builder.graph.digraph import Digraph
-
-
-@six.add_metaclass(abc.ABCMeta)
-class PluginBase(object):
-    """Abstract base class for block device plugins"""
-
-    def __init__(self, name):
-        """All plugins must have a name"""
-        self.name = name
-
-    @abc.abstractmethod
-    def create(self, state, rollback):
-        """Create the block device plugin
-
-        :param state: a dictionary to store results for this plugin.
-                      These are used in two scenarios: other plugins
-                      can use this to get information about the
-                      result of the plugin and it can be used in
-                      later runs of dib-block-device for cleaning up.
-        :type state: dict(str:?)
-
-        :param rollback: a list of python functions that will be
-                         called in reversed order to cleanup if there
-                         occurs an error later within the same
-                         dib-block-device run.
-        :type rollback: list(function)
-        """
-
-
-class NodePluginBase(PluginBase, Digraph.Node):
-
-    def insert_nodes(self, dg):
-        """Adds self as a node to the given digraph"""
-        dg.add_node(self)