Add Init_rc to Product_variables.Eng

Change-Id: If490b64f3631ec0825ffa28964a3e65572a9bcb8

android/variable.go

@@ -153,6 +153,7 @@ type variableProperties struct {
 		Eng struct {
 			Cflags   []string
 			Cppflags []string
+			Init_rc  []string
 			Lto      struct {
 				Never *bool
 			}