x/tools/dashboard/app: ignore freebsd-arm failures

TBR=dfc
R=dave
CC=golang-codereviews
https://golang.org/cl/179820043
diff --git a/dashboard/app/build/notify.go b/dashboard/app/build/notify.go
index 09ed03d..1a71dd2 100644
--- a/dashboard/app/build/notify.go
+++ b/dashboard/app/build/notify.go
@@ -38,6 +38,7 @@
 var ignoreFailure = map[string]bool{
 	"dragonfly-386":         true,
 	"dragonfly-amd64":       true,
+	"freebsd-arm":           true,
 	"netbsd-amd64-bsiegert": true,
 	"netbsd-arm-rpi":        true,
 	"plan9-amd64-aram":      true,