Allow for overriding container packagename for an Apex.

Test: go test ./... -test.v -run TestOverrideApex
BUG: 148198056
Change-Id: If49042a7acbf9f0dcb505664863d97805902e459
diff --git a/apex/apex.go b/apex/apex.go
index cddd72b..1855841 100644
--- a/apex/apex.go
+++ b/apex/apex.go
@@ -1359,6 +1359,10 @@
 
 	// Logging Parent value
 	Logging_parent string
+
+	// Apex Container Package Name.
+	// Override value for attribute package:name in AndroidManifest.xml
+	Package_name string
 }
 
 type apexPackaging int