Correct some search problems

* correct the syntax in the example yaml file to use "change:"
* an error caused it to attempt to sync by number when using a change id
* define the change_id token with a function so that it is ordered
  in the lexer and takes precedence over strings

Change-Id: Ic48193ffd0a16f84b83f7c045ab990699fd8c755

gertty.yaml-sample

@@ -29,7 +29,7 @@ commentlinks:
     replacements:
       - search:
           text: "{id}"
-          query: "changeid:{id}"
+          query: "change:{id}"
 
 # This is the query used for the list of changes when a project is
 # selected.  The default is "status:open"; if you don't want to see

gertty/app.py

@@ -226,6 +226,7 @@ class App(object):
             try:
                 number = int(number)
             except ValueError:
+                number = None
                 changeid = query.split(':')[1].strip()
         if not (number or changeid):
             return

gertty/commentlink.py

@@ -51,7 +51,7 @@ class SearchReplacement(object):
     def replace(self, app, data):
         link = mywid.Link(self.text.format(**data), 'link', 'focused-link')
         urwid.connect_signal(link, 'selected',
-            lambda link:app.search(self.query.format(**data)))
+            lambda link:app.doSearch(self.query.format(**data)))
         return link
 
 class CommentLink(object):

gertty/search/tokenizer.py

@@ -68,7 +68,6 @@ tokens = [
     ] + operators.values()
 
 def SearchTokenizer():
-    t_CHANGE_ID  = r'I[a-fA-F0-9]{7,40}'
     t_LPAREN     = r'\('
     t_RPAREN     = r'\)'
     t_NEG        = r'!'
@@ -78,6 +77,10 @@ def SearchTokenizer():
         t.type = operators.get(t.value[:-1], 'OP')
         return t
 
+    def t_CHANGE_ID(t):
+        r'I[a-fA-F0-9]{7,40}'
+        return t
+
     def t_SSTRING(t):
         r"'([^\\']+|\\'|\\\\)*'"
         t.value=t.value[1:-1].decode("string-escape")