infra: fix typos in luci-scheduler.cfg.

TBR=kbr@chromium.org

No-Try: True
Change-Id: I3b6e7a4bfe81a67b0d67b334b09217fd02b2c579
Reviewed-on: https://chromium-review.googlesource.com/996638
Commit-Queue: Andrii Shyshkalov <tandrii@chromium.org>
Reviewed-by: Kenneth Russell <kbr@chromium.org>
Reviewed-by: Andrii Shyshkalov <tandrii@chromium.org>
Cr-Commit-Position: refs/heads/master@{#548234}

infra/config/global/luci-scheduler.cfg

@@ -754,7 +754,7 @@ job {
   buildbucket: {
     server: "cr-buildbucket.appspot.com"
     bucket: "luci.chromium.ci"
-    builder: "Mac Release (Intel)"
+    builder: "Mac Debug (Intel)"
   }
 }
 
@@ -853,7 +853,7 @@ job {
   buildbucket: {
     server: "cr-buildbucket.appspot.com"
     bucket: "luci.chromium.ci"
-    builder: "Mac Retina Release (AMD)"
+    builder: "Mac Retina Debug (AMD)"
   }
 }