ovsdb-idl: Fix memory leak of ovsdb_idl_db_clear.

ovsdb_idl_row_destroy() doesn't free the memory of row structure itself.
This is because of the ovsdb change tracking feature: the deleted row
may be accessed in the current iteration of main loop. The function
ovsdb_idl_row_destroy_postprocess() is called at the end of
ovsdb_idl_run() to free the deleted rows that are not tracked; the
function ovsdb_idl_db_track_clear() is called (indirectly) by user
at the end of each main loop iteration to free the deleted rows that
are tracked. However, in ovsdb_idl_db_clear(), which may be called when
a session is reset, or when the idl is destroyed, it didn't call
ovsdb_idl_row_destroy_postprocess(), which would result in all the
untracked rows leaked. This patch fixes that.

Signed-off-by: Han Zhou <[email protected]>
Signed-off-by: Ben Pfaff <[email protected]>

lib/ovsdb-idl.c

@@ -617,6 +617,7 @@ ovsdb_idl_db_clear(struct ovsdb_idl_db *db)
             ovsdb_idl_row_destroy(row);
         }
     }
+    ovsdb_idl_row_destroy_postprocess(db);
 
     db->cond_changed = false;
     db->cond_seqno = 0;