convert: call superclass init from engine init functions

hgext/convert/common.py

@@ -17,7 +17,7 b' class converter_source(object):'
     def __init__(self, ui, path, rev=None):
         """Initialize conversion source (or raise NoRepo("message")
         exception if path is not a valid repository)"""
-        raise NotImplementedError()
+        pass
 
     def getheads(self):
         """Return a list of this repository's heads"""

hgext/convert/cvs.py

@@ -7,6 +7,8 b' from common import NoRepo, commit, conve'
 
 class convert_cvs(converter_source):
     def __init__(self, ui, path, rev=None):
+        super(convert_cvs, self).__init__(ui, path, rev=rev)
+
         self.path = path
         self.ui = ui
         self.rev = rev

hgext/convert/git.py

@@ -9,6 +9,8 b' class convert_git(converter_source):'
         return os.popen('GIT_DIR=%s %s' % (self.path, s))
 
     def __init__(self, ui, path, rev=None):
+        super(convert_git, self).__init__(ui, path, rev=rev)
+
         if os.path.isdir(path + "/.git"):
             path += "/.git"
         if not os.path.exists(path + "/objects"):

hgext/convert/subversion.py

@@ -77,6 +77,8 b' class svn_paths(object):'
 # SVN conversion code stolen from bzr-svn and tailor
 class convert_svn(converter_source):
     def __init__(self, ui, url, rev=None):
+        super(convert_svn, self).__init__(ui, url, rev=rev)
+
         try:
             SubversionException
         except NameError: