[infer][ondemand] remove redundancy when storing summaries to disk

Summary:
It seems that what `Checkers.ST.store_summary` was called witin on-demand was actually redundant with what `Ondemand` is doing before storing the summaries.

This also makes the `Ondemand` module no longer depend on `Checkers` as the dependency is expected to be the other way around.

Reviewed By: sblackshear

Differential Revision: D4595006

fbshipit-source-id: d62187e

infer/src/backend/ondemand.ml

@@ -152,8 +152,7 @@ let run_proc_analysis ~propagate_exceptions analyze_proc curr_pdesc callee_pdesc
       { summary with
         Specs.status = Specs.INACTIVE;
         timestamp = summary.Specs.timestamp + 1 } in
-    Specs.add_summary callee_pname summary';
-    Checkers.ST.store_summary callee_pname;
+    Specs.store_summary callee_pname summary';
     Printer.write_proc_html source false callee_pdesc;
     summary' in