MSRuleCleaner: local variable 'transferInfo' referenced before assignment
**Impact of the bug**
MSRuleCleaner

**Describe the bug**
While testing another and unrelated PR, one unit test failed and part of the error message is:
```
  File "/build/cmsbld/jenkins/workspace/DMWM-WMCorePy3-PR-unittests/SLICE/3/label/cms-dmwm-cc7/code/src/python/WMCore/MicroService/MSRuleCleaner/MSRuleCleaner.py", line 632, in getMSOutputTransferInfo
    if transferInfo is None:
local variable 'transferInfo' referenced before assignment
```

here is the full unit test log (which will become unavailable in 30 days from now):
https://cmssdt.cern.ch/dmwm-jenkins/job/DMWM-WMCore-PR-test/13970/testReport/junit/WMCore_t.MicroService_t.MSRuleCleaner_t.MSRuleCleaner_t/MSRuleCleanerTest/testRunning/

**How to reproduce it**
Make that code to execute the exception block

**Expected behavior**
That unexpected exception should not occur.

**Additional context and error message**
None
diff --git a/src/python/WMCore/MicroService/MSRuleCleaner/MSRuleCleaner.py b/src/python/WMCore/MicroService/MSRuleCleaner/MSRuleCleaner.py
index 8d5807aa3..54d1cd049 100644
--- a/src/python/WMCore/MicroService/MSRuleCleaner/MSRuleCleaner.py
+++ b/src/python/WMCore/MicroService/MSRuleCleaner/MSRuleCleaner.py
@@ -625,6 +625,7 @@ class MSRuleCleaner(MSCore):
             data = json.loads(res)['result'][0]
             transferInfo = data['transferDoc']
         except Exception as ex:
+            transferInfo = None
             msg = "General exception while fetching TransferInfo from MSOutput for %s. "
             msg += "Error: %s"
             self.logger.exception(msg, wflow['RequestName'], str(ex))
['src/python/WMCore/MicroService/MSRuleCleaner/MSRuleCleaner.py']