fix: Reorder pilot downloads to minimise race condition

Author: sfayer

src/DIRAC/WorkloadManagementSystem/Utilities/PilotWrapper.py

@@ -193,7 +193,7 @@ def pilotWrapperScript(
       from urllib.request import urlopen as url_library_urlopen
       from urllib.error import URLError as url_library_URLError
 
-    for fileName in ['pilot.json', 'pilot.tar', 'checksums.sha512']:
+    for fileName in ['checksums.sha512', 'pilot.json', 'pilot.tar']:
       # needs to distinguish whether urlopen method contains the 'context' param
       # in theory, it should be available from python 2.7.9
       # in practice, some prior versions may be composed of recent urllib version containing the param