Variable `file` out of scope - pylint complains - not critical
**Impact of the bug**
`src/python/WMCore/WMRuntime/Monitors/TestMonitor.py`, so i assume this is not critical.

**Describe the bug**
While running `pylint --py3k` working on #10440, pylint complained about the line

https://github.com/dmwm/WMCore/blob/dd63a901a9b929d83cbe83e9a2f9004e0901a90c/src/python/WMCore/WMRuntime/Monitors/TestMonitor.py#L155

with the warning `file built-in referenced (file-builtin)`. However, (as far as i understand) here we are using the variable `file` out of scope (it is not defined in the class `TestMonitor`), so pylint thinks we are using the python2 reserved keyword `file` (which is not a reserved keyword anymore in py3) and complains.

I propose to define the variable file as a `TestMonitor` class member, and maybe also change its name to a non-reserved keyword while we are at it. Maybe `self.cmsswFile` is what we should use in that line instead of `file`?

**How to reproduce it**
Run
```bash
pylint --py3k -d W1618,W1619 src/python/WMCore/WMRuntime/Monitors/TestMonitor.py
```

**Expected behavior**
We would like pylint not to complain (not too much, at least)


diff --git a/src/python/WMCore/WMRuntime/Monitors/TestMonitor.py b/src/python/WMCore/WMRuntime/Monitors/TestMonitor.py
index dd4fbf46b..f7a0ffb85 100644
--- a/src/python/WMCore/WMRuntime/Monitors/TestMonitor.py
+++ b/src/python/WMCore/WMRuntime/Monitors/TestMonitor.py
@@ -152,7 +152,7 @@ class TestMonitor(WMRuntimeMonitor):
 
         # Check for events
         if self.cmsswFile:
-            run, event = searchForEvent(file)
+            run, event = searchForEvent(self.cmsswFile)
             if run and event:
                 # Then we actually found something, otherwise do nothing
                 # Right now I don't know what to do
['src/python/WMCore/WMRuntime/Monitors/TestMonitor.py']