nmbug-status: Wrap query phrases in parentheses when and-ing together

For example:

  "query": ["tag:a", "tag:b or tag:c"]

is now converted to:

  ( tag:a ) and ( tag:b or tag:c )

instead of the old:

  tag:a and tag:b or tag:c

This helps us avoid confusion due to Xapian's higher-precedence AND
[1], where the old query would be interpreted as:

  ( tag:a and tag:b ) or tag:c

[1]: http://xapian.org/docs/queryparser.html

NEWS

@@ -4,6 +4,9 @@ Notmuch 0.22 (UNRELEASED)
 nmbug-status
 ------------
 
+`nmbug-status` now wraps query phrases in parentheses when and-ing
+them together, to avoid confusion about clause grouping.
+
 `nmbug-status` now supports `meta.message-url` to override the Gmane
 template.  For example, you can use:
 

devel/nmbug/nmbug-status

@@ -167,7 +167,8 @@ class Page (object):
                 view['title'], sort_key))
         if 'query-string' not in view:
             query = view['query']
-            view['query-string'] = ' and '.join(query)
+            view['query-string'] = ' and '.join(
+                '( {} )'.format(q) for q in query)
         q = notmuch.Query(database, view['query-string'])
         q.set_sort(sort)
         threads = self._get_threads(messages=q.search_messages())
@@ -421,7 +422,7 @@ if args.list_views:
 elif args.get_query != None:
     for view in config['views']:
         if args.get_query == view['title']:
-            print(' and '.join(view['query']))
+            print(' and '.join('( {} )'.format(q) for q in view['query']))
     sys.exit(0)
 else:
     # only import notmuch if needed