Add override_module.

This new module type replaces the inherit-package function in make by
allowing developers to override the name, the certificate, and the
manifest package name of an android_app module.

Bug: 122957760
Fixes: 123640028
Test: app_test.go + BrowserGoogle
Change-Id: Iefe447e7078b25039233221361ef95c83a29973a
diff --git a/apex/apex.go b/apex/apex.go
index 9ab5187..5d0c52a 100644
--- a/apex/apex.go
+++ b/apex/apex.go
@@ -534,7 +534,7 @@
 func (a *apexBundle) getCertString(ctx android.BaseContext) string {
 	certificate, overridden := ctx.DeviceConfig().OverrideCertificateFor(ctx.ModuleName())
 	if overridden {
-		return ":" + certificate
+		return certificate
 	}
 	return String(a.properties.Certificate)
 }