Fix missing date of month in network graph when commits span a month

Closes #3635, #1383

CHANGELOG

 Please view this file on the master branch, on stable branches it's out of date.
 v 8.4.0 (unreleased)
+  - Fix missing date of month in network graph when commits span a month (Stan Hu)
   - Expire view caches when application settings change (e.g. Gravatar disabled) (Stan Hu)
   - Don't notify users twice if they are both project watchers and subscribers (Stan Hu)
   - Implement new UI for group page

app/assets/javascripts/branch-graph.js.coffee

@@ -66,7 +66,7 @@ class @BranchGraph
     r.rect(40, 0, 30, @barHeight).attr fill: "#444"
     for day, mm in @days
-      if cuday isnt day[0]
+      if cuday isnt day[0] || cumonth isnt day[1]
         # Dates
         r.text(55, @offsetY + @unitTime * mm, day[0])
           .attr(