Merge pull request tensorflow#2414 from xcyan/fix_2240

Fix 2240 [PTN]: Remove the default value in 'master' flag

Author: nealwu

research/ptn/eval_rotator.py

@@ -64,7 +64,7 @@
 flags.DEFINE_integer('save_summaries_secs', 15, '')
 flags.DEFINE_integer('eval_interval_secs', 60 * 5, '')
 # Scheduling
-flags.DEFINE_string('master', 'local', '')
+flags.DEFINE_string('master', '', '')
 
 FLAGS = flags.FLAGS