[python] do not crash when reporting invalid locales

Summary:
When `LC_CTYPE` has an invalid value, `locale.getdefaultlocale()` raises
`ValueError` and infer crashes, which is embarrassing. Catch these errors and
report appropriately.

fixes #483

Reviewed By: akotulski

Differential Revision: D4182880

fbshipit-source-id: 31edcf7

infer/lib/python/infer.py

@@ -157,8 +157,12 @@ def main():
                                  touch_if_present=not args.continue_capture)
 
         utils.configure_logging(args)
-        logging.info('output of locale.getdefaultlocale(): %s',
-                     str(locale.getdefaultlocale()))
+        try:
+            logging.info('output of locale.getdefaultlocale(): %s',
+                         str(locale.getdefaultlocale()))
+        except (locale.Error, ValueError) as e:
+            logging.info('locale.getdefaultlocale() failed with exception: %s',
+                         str(e))
         logging.info('encoding we chose in the end: %s',
                      config.CODESET)
         logging.info('Running command %s',