Fixes #1548 by correctly reporting a locked file. Allows to run several RIDE

instances simultaneously.

Author: HelioGuilherme66

src/robotide/log/log.py

@@ -56,7 +56,7 @@ def _remove_old_log_files(self):
             try:
                 os.remove(fname)
             except OSError or IOError as e:
-                sys.stderr.write(e)
+                sys.stderr.write("{}".format(e))
 
     @property
     def _logfile(self):