Merge pull request #1073 from danimo/fix_osm_tiles_for_https

Use protocol relative URL when loading OSM tiles

app/views/conference/_venue_map.html.haml

@@ -5,7 +5,7 @@
     // create a map in the "map" div, set the view to a given place and zoom
     var map = L.map('map', { scrollWheelZoom: false }).setView([#{@conference.venue.latitude}, #{@conference.venue.longitude}], 11);
     // add an OpenStreetMap tile layer
-    L.tileLayer('http://{s}.tile.osm.org/{z}/{x}/{y}.png', {
+    L.tileLayer('//{s}.tile.openstreetmap.org/{z}/{x}/{y}.png', {
       attribution: 'Map data &copy; <a href="http://openstreetmap.org">OpenStreetMap</a> contributors, <a href="http://creativecommons.org/licenses/by-sa/2.0/">CC-BY-SA</a>, Imagery © <a href="http://mapbox.com">Mapbox</a>',
       maxZoom: 18
     }).addTo(map);