Python 3: use "as" instead of comma in except clause

tools/data_source/data_source.py

@@ -88,7 +88,7 @@ def __main__():
                 page = urllib.urlopen( cur_URL )
             elif URL_method == 'post':
                 page = urllib.urlopen( cur_URL, urllib.urlencode( params ) )
-        except Exception, e:
+        except Exception as e:
             stop_err( 'The remote data source application may be off line, please try again later. Error: %s' % str( e ) )
         if max_file_size:
             file_size = int( page.info().get( 'Content-Length', 0 ) )
@@ -97,14 +97,14 @@ def __main__():
         # do sniff stream for multi_byte
         try:
             cur_filename, is_multi_byte = sniff.stream_to_open_named_file( page, os.open( cur_filename, os.O_WRONLY | os.O_CREAT ), cur_filename, source_encoding=get_charset_from_http_headers( page.headers ) )
-        except Exception, e:
+        except Exception as e:
             stop_err( 'Unable to fetch %s:\n%s' % ( cur_URL, e ) )
 
         # here import checks that upload tool performs
         if enhanced_handling:
             try:
                 ext = sniff.handle_uploaded_dataset_file( filename, datatypes_registry, ext=data_dict[ 'ext' ], is_multi_byte=is_multi_byte )
-            except Exception, e:
+            except Exception as e:
                 stop_err( str( e ) )
             info = dict( type='dataset',
                          dataset_id=data_dict[ 'dataset_id' ],