fix crash if file removed by external

Script/ManagerThread.py

@@ -239,8 +239,19 @@ class ManagerThread(threading.Thread):
                 # end if
 
                 ### Check for minimal file size, if needed
+                try:
+                    filesize = os.path.getsize(filename)
+                except OSError as exc:
+                    if exc.errno == errno.ENOENT:
+                        # The file has been removed by an external cause.
+                        # This is bad but this is not a reason to crash.
+                        self.logger.critical('error getting file size for %s: not present (deleted by external cause)', filename)
+                        continue
+                    else:
+                        raise exc
+
                 if self.MinSizekB and \
-                   os.path.getsize(filename)/1024.< self.MinSizekB:
+                   filesize/1024.< self.MinSizekB:
                     self.logger.debug('File %s is too small. Skipping.', filename)
                     if self.RemoveSmallFiles:
                         self.logger.debug('File %s is too small. Deleting.', filename)