[milo] remove linkBase and calculate links directly.

milo/buildsource/swarming/expectations/build-canceled.json

Index: milo/buildsource/swarming/expectations/build-canceled.json
diff --git a/milo/buildsource/swarming/expectations/build-canceled.json b/milo/buildsource/swarming/expectations/build-canceled.json
index a3f92b475c102cda1288d65b1cad42321a155508..7e137dc4db40666cbd53c5b80f58bdb2e571c341 100644
--- a/milo/buildsource/swarming/expectations/build-canceled.json
+++ b/milo/buildsource/swarming/expectations/build-canceled.json
@@ -39,7 +39,7 @@
       [
         {
           "Label": "stdout",
-          "URL": "foo/stdout"
+          "URL": "/swarming/task/build-canceled/stdout"
         }
       ]
     ],
@@ -61,7 +61,7 @@
       "MainLink": [
         {
           "Label": "stdout",
-          "URL": "foo/steps/recipe_bootstrap/0/stdout"
+          "URL": "/swarming/task/build-canceled/steps/recipe_bootstrap/0/stdout"
         }
       ],
       "Started": "2016-03-14T10:00:02Z",
@@ -78,14 +78,14 @@
       "MainLink": [
         {
           "Label": "stdout",
-          "URL": "foo/steps/setup_build/0/stdout"
+          "URL": "/swarming/task/build-canceled/steps/setup_build/0/stdout"
         }
       ],
       "SubLink": [
         [
           {
             "Label": "run_recipe",
-            "URL": "foo/steps/setup_build/0/logs/run_recipe/0"
+            "URL": "/swarming/task/build-canceled/steps/setup_build/0/logs/run_recipe/0"
           }
         ]
       ],