DL-29: The merge PR script should delete branches once the PR are merged

Author: Sijie Guo <sijieg@twitter.com>

Reviewers: Franck Cuny <franck.cuny@gmail.com>

Closes #24 from sijie/sijie/fix_merge_script

scripts/dev/dl-merge-pr.py

@@ -139,7 +139,7 @@ def clean_up():
     print('Restoring head pointer to {0}'.format(original_head))
     run_cmd(['git', 'checkout', original_head])
 
-  branches = run_cmd(['git', 'branch']).rstrip().split('\n')
+  branches = run_cmd(['git', 'branch']).strip().split('\n')
 
   for branch in filter(lambda x: x.startswith(TEMP_BRANCH_PREFIX), branches):
     print('Deleting local branch {0}'.format(branch))
@@ -431,7 +431,19 @@ def get_reviewers(pr_num):
   reviewers_emails = []
   for reviewer_id in reviewers_ids:
     user = get_json('{0}/users/{1}'.format(GITHUB_API_URL, reviewer_id))
-    reviewers_emails += ['{0} <{1}>'.format(user['name'].strip(), user['email'].strip())]
+    username = None
+    useremail = None
+    if user['email'] is not None:
+        useremail = user['email'].strip()
+    else:
+        useremail = None
+    if user['name'] is not None:
+        username = user['name'].strip()
+    else:
+        username = useremail
+    if username is None:
+        continue
+    reviewers_emails += ['{0} <{1}>'.format(username, useremail)]
   return ', '.join(reviewers_emails)