reader: scrub JGF fetcher status value

Problem: when the JGF reader encounters a vertex with
its status specified in the JGF, the fetcher sets its
status appropriately but does not scrub the value.
This causes all subsequently fetched vertices to
inherit the value.

Add a line to reset the status to the JGF default value
in scrub ().

resource/readers/resource_reader_jgf.cpp

@@ -139,6 +139,7 @@ void fetch_helper_t::scrub ()
     size = -1;
     uniq_id = -1;
     exclusive = -1;
+    status = resource_pool_t::status_t::UP;
     type = NULL;
     name = NULL;
     unit = NULL;