LUCENE-7265: Fix addVersion to cherry-pick downstream changes by using the change id

dev-tools/scripts/addVersion.py

@@ -186,7 +186,10 @@ def read_config():
   return c
   
 def main():
-  c = read_config() 
+  c = read_config()
+
+  if c.changeid:
+    cherry_pick_change(c.changeid)
 
   print('\nAdding new version %s' % c.version)
   update_changes('lucene/CHANGES.txt', c.version)

dev-tools/scripts/scriptutil.py

@@ -121,6 +121,11 @@ version_prop_re = re.compile('version\.base=(.*)')
 def find_current_version():
   return version_prop_re.search(open('lucene/version.properties').read()).group(1)
 
+def cherry_pick_change(changeid):
+  print('\nCherry-picking downstream change %s...' % changeid, end='')
+  run('git cherry-pick %s' % changeid)
+  print('done')
+
 if __name__ == '__main__':
   print('This is only a support module, it cannot be run')
   sys.exit(1)