Flush subprocess stdout before trying to read from it

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1491146 13f79535-47bb-0310-9956-ffa450edef68

dev-tools/scripts/buildAndPushRelease.py

@@ -49,6 +49,7 @@ def runAndSendGPGPassword(command, password):
   p = subprocess.Popen(command, shell=True, bufsize=0, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, stdin=subprocess.PIPE)
   f = open(LOG, 'ab')
   while True:
+    p.stdout.flush()
     line = p.stdout.readline()
     if len(line) == 0:
       break