Stop using deepcopy in primary.xml processing to speed up sync

closes #2466
https://pulp.plan.io/issues/2466

plugins/pulp_rpm/plugins/importers/yum/repomd/primary.py

@@ -1,6 +1,5 @@
 # -*- coding: utf-8 -*-
 
-from copy import deepcopy
 import os
 
 from pulp.server import util
@@ -78,22 +77,6 @@
                        'sourcerpm': None,
                        'files': []}
 
-# RPM entry dictionary ---------------------------------------------------------
-
-# RPM entry dictionaries will make up the values in the requires and provides lists
-
-RPM_ENTRY_SKEL = {'name': None,
-                  'version': None,
-                  'release': None,
-                  'epoch': None,
-                  'flags': None}
-
-# file information dictionary --------------------------------------------------
-
-# file information dictionaries will make up the values in the files lists
-
-FILE_INFO_SKEL = {'path': None}
-
 # element processing methods ---------------------------------------------------
 
 
@@ -107,9 +90,6 @@ def process_package_element(package_element):
     :return: package information dictionary
     :rtype: pulp_rpm.plugins.db.models.RPM
     """
-    # NOTE the use of deepcopy relies on cpython's very sensible policy of never
-    # duplicating string literals, this may not hold up in other implementations
-    # the python interpreter.
     package_info = dict()
 
     name_element = package_element.find(NAME_TAG)
@@ -195,9 +175,6 @@ def _process_format_element(format_element):
     :return: package format dictionary
     :rtype: dict
     """
-    # NOTE the use of deepcopy relies on cpython's very sensible policy of never
-    # duplicating string literals, this may not hold up in other implementations
-    # the python interpreter.
     package_format = dict()
 
     if format_element is None:
@@ -254,10 +231,7 @@ def _process_rpm_entry_element(rpm_entry_element):
     :return: RPM entry dictionary
     :rtype: dict
     """
-    # NOTE the use of deepcopy relies on cpython's very sensible policy of never
-    # duplicating string literals, this may not hold up in other implementations
-    # the python interpreter.
-    rpm_entry = deepcopy(RPM_ENTRY_SKEL)
+    rpm_entry = dict()
 
     rpm_entry['name'] = rpm_entry_element.attrib['name']
     rpm_entry['version'] = rpm_entry_element.attrib.get('ver', None)
@@ -277,10 +251,7 @@ def _process_file_element(file_element):
     :return: file information dictionary
     :rtype: dict
     """
-    # NOTE the use of deepcopy relies on cpython's very sensible policy of never
-    # duplicating string literals, this may not hold up in other implementations
-    # the python interpreter.
-    file_info = deepcopy(FILE_INFO_SKEL)
+    file_info = dict()
 
     file_info['path'] = file_element.text