convert: fix relative import of stdlib module in subversion Before this patch, import-checker reports "relative import of stdlib module" error for importing Pool and SubversionException from svn.core in subversion.py. To fix this relative import of stdlib module, this patch adds prefix 'svn.core.' to Pool and SubversionException in source. These 'svn.core.' relative accessing shouldn't cause performance impact, because there are much more code paths accessing to 'svn.core.' relative properties. BTW, in transport.py, this error is avoided by assignment below. SubversionException = svn.core.SubversionException But this can't be used in subversion.py case, because: - such assignment in indented code block causes "don't use camelcase in identifiers" error of check-code.py - but it should be placed in indented block, because svn is None at failure of importing subversion python binding libraries (= examination of 'svn' is needed)