init: add a hook before parsing system properties

Also properly implement weak symbol overridden while at it.

Change-Id: Id563c8aaa52c0e41823dbb035f0319a6531f12b7
Signed-off-by: micky387 <mickaelsaibi@free.fr>
diff --git a/init/property_service.cpp b/init/property_service.cpp
index ea4860e..e7bf97c 100644
--- a/init/property_service.cpp
+++ b/init/property_service.cpp
@@ -1425,6 +1425,8 @@
     ProcessKernelCmdline();
     ProcessBootconfig();
 
+    vendor_process_bootenv();
+
     // Propagate the kernel variables to internal variables
     // used by init as well as the current required properties.
     ExportKernelBootProps();