wic: throw exception if required API is not implemented

Throw WicError if do_create method of imager plugin is
not implemented.

(From OE-Core rev: 87031c933047a37ddc26be3d04ea17b6e60ea10a)

Signed-off-by: Ed Bartosh <ed.bartosh@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

scripts/lib/wic/pluginbase.py

@@ -21,6 +21,8 @@ import logging
 
 from collections import defaultdict
 
+from wic import WicError
+
 logger = logging.getLogger('wic')
 
 class PluginMeta(type):
@@ -35,6 +37,10 @@ class PluginMeta(type):
 class ImagerPlugin(metaclass=PluginMeta):
     wic_plugin_type = "imager"
 
+    def do_create(self):
+        raise WicError("Method %s.do_create is not implemented" %
+                       self.__class__.__name__)
+
 class SourcePlugin(metaclass=PluginMeta):
     wic_plugin_type = "source"
     """