cooker: remove command import in cooker.py

There is no direct use of command in cooker.py, and it is using
bb.command instead. Remove command in the import list.

This fixes a problem of embedded import between command.py and
cooker.py.

(Bitbake rev: c353316b2efcc7a893d6b4aa9a9647d51a6f69e3)

Signed-off-by: Dongxiao Xu <dongxiao.xu@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/event.py

@@ -402,6 +402,14 @@ class FilesMatchingFound(Event):
         self._pattern = pattern
         self._matches = matches
 
+class CoreBaseFilesFound(Event):
+    """
+    Event when a list of appropriate config files has been generated
+    """
+    def __init__(self, paths):
+        Event.__init__(self)
+        self._paths = paths
+
 class ConfigFilesFound(Event):
     """
     Event when a list of appropriate config files has been generated