devapp/owners: use gophers.Person.Gerrit

Currently the same as Emails[0], but the gophers package is the right
place to centralize that logic.

Change-Id: I6cc4fd36d76b94d7a4a49c36e3d5a30d6088850c
Reviewed-on: https://go-review.googlesource.com/c/build/+/192102
Run-TryBot: Filippo Valsorda <filippo@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
diff --git a/devapp/owners/table.go b/devapp/owners/table.go
index 25e1ce6..d4b0c16 100644
--- a/devapp/owners/table.go
+++ b/devapp/owners/table.go
@@ -13,10 +13,10 @@
 	if p == nil {
 		panic(githubUsername + " not found")
 	}
-	if len(p.Emails) == 0 {
+	if p.Gerrit == "" {
 		panic("person with GitHub username " + githubUsername + " must have at least one email")
 	}
-	return Owner{GitHubUsername: githubUsername, GerritEmail: p.Emails[0]}
+	return Owner{GitHubUsername: githubUsername, GerritEmail: p.Gerrit}
 }
 
 var (