Replace prodcertstatus with gcertstatus

Prodaccess is apparently deprecated now.

Test: Build with/without credentials and check that it works

Change-Id: Iaadaebe84fe9531b2d7d5f0d265751462bb827d8
diff --git a/ui/build/config.go b/ui/build/config.go
index 8ec9680..7a40965 100644
--- a/ui/build/config.go
+++ b/ui/build/config.go
@@ -1486,7 +1486,7 @@
 	if googleProdCredsExistCache {
 		return googleProdCredsExistCache
 	}
-	if _, err := exec.Command("/usr/bin/prodcertstatus", "--simple_output", "--nocheck_loas").Output(); err != nil {
+	if _, err := exec.Command("/usr/bin/gcertstatus").Output(); err != nil {
 		return false
 	}
 	googleProdCredsExistCache = true