Fix make_corpus warning message (#284)

Currently, the warning message is specified using logging.warn rather
than logging.warning and the former is deprecated. This patch also adds
appropriate spacing and fixes spelling to make the message appear as
intended.

Author: boomanaiden154

compiler_opt/tools/make_corpus.py

@@ -42,10 +42,11 @@
 
 
 def main(_):
-  logging.warn('Using this tool does not guarnatee that the bitcode is taken at'
-               'the correct stage for consumption during model training. Make'
-               'sure to validate assumptions about where the bitcode is coming'
-               'from before using it in production.')
+  logging.warning(
+      'Using this tool does not guarantee that the bitcode is taken at '
+      'the correct stage for consumption during model training. Make '
+      'sure to validate assumptions about where the bitcode is coming '
+      'from before using it in production.')
   relative_paths = make_corpus_lib.load_bitcode_from_directory(FLAGS.input_dir)
   make_corpus_lib.copy_bitcode(relative_paths, FLAGS.input_dir,
                                FLAGS.output_dir)