LUCI migraiton is over. Remove luci-migration app permissions.

R=jbudorick

Bug: 988217
Change-Id: I380cca75ce78086e5768b2c4dfa5e5464487d8d1
No-Try: True
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1826055
Auto-Submit: Andrii Shyshkalov <tandrii@google.com>
Commit-Queue: John Budorick <jbudorick@chromium.org>
Reviewed-by: John Budorick <jbudorick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#700058}

infra/config/cr-buildbucket-dev.cfg

@@ -41,11 +41,6 @@ acl_sets {
     role: WRITER
     group: "service-account-chromium-tryserver"
   }
-  acls {
-    # Allow luci-migration to bump next build number.
-    role: WRITER
-    identity: "luci-migration@appspot.gserviceaccount.com"
-  }
 }
 
 builder_mixins {

infra/config/cr-buildbucket.cfg

@@ -38,11 +38,6 @@ acl_sets {
     role: WRITER
     group: "google/luci-task-force@google.com"
   }
-  acls {
-    # Allow luci-migration to bump next build number.
-    role: WRITER
-    identity: "luci-migration@appspot.gserviceaccount.com"
-  }
 }
 
 acl_sets {
@@ -72,11 +67,6 @@ acl_sets {
     role: WRITER
     group: "service-account-chromium-tryserver"
   }
-  acls {
-    # Allow luci-migration to bump next build number.
-    role: WRITER
-    identity: "luci-migration@appspot.gserviceaccount.com"
-  }
 }
 
 # CI builders (of which are few) may use high number of concurrent Goma jobs.