Fix "Unknown error loading Dockerfile information" error

`ImageDistGitRepo.org_image_name,org_version,org_release` should be
declared before calling the constructor of the base class. This is
because the constructor of the base class may call `clone()` method to
set those fields internally.

doozerlib/distgit.py

@@ -416,6 +416,9 @@ class ImageDistGitRepo(DistGitRepo):
 
     def __init__(self, metadata, autoclone=True,
                  source_modifier_factory=SourceModifierFactory()):
+        self.org_image_name = None
+        self.org_version = None
+        self.org_release = None
         super(ImageDistGitRepo, self).__init__(metadata, autoclone=autoclone)
         self.build_lock = Lock()
         self.build_lock.acquire()
@@ -424,10 +427,6 @@ def __init__(self, metadata, autoclone=True,
         self.logger: logging.Logger = metadata.logger
         self.source_modifier_factory = source_modifier_factory
 
-        self.org_image_name = None
-        self.org_version = None
-        self.org_release = None
-
     def clone(self, distgits_root_dir, distgit_branch):
         super(ImageDistGitRepo, self).clone(distgits_root_dir, distgit_branch)
         self._read_master_data()