flow/storage: use const for getter

src/flow-storage.c

@@ -36,7 +36,7 @@ unsigned int FlowStorageSize(void)
     return StorageGetSize(STORAGE_FLOW);
 }
 
-void *FlowGetStorageById(Flow *f, FlowStorageId id)
+void *FlowGetStorageById(const Flow *f, FlowStorageId id)
 {
     return StorageGetById((Storage *)((void *)f + sizeof(Flow)), STORAGE_FLOW, id.id);
 }

src/flow-storage.h

@@ -35,7 +35,7 @@ typedef struct FlowStorageId {
 
 unsigned int FlowStorageSize(void);
 
-void *FlowGetStorageById(Flow *h, FlowStorageId id);
+void *FlowGetStorageById(const Flow *h, FlowStorageId id);
 int FlowSetStorageById(Flow *h, FlowStorageId id, void *ptr);
 void *FlowAllocStorageById(Flow *h, FlowStorageId id);
 

src/output-json.c

@@ -767,7 +767,7 @@ static int CreateJSONEther(JsonBuilder *js, const Packet *p, const Flow *f)
     } else if (f != NULL) {
         /* we are creating an ether object in a flow context, so we need to
            append to arrays */
-        MacSet *ms = FlowGetStorageById((Flow *)f, MacSetGetFlowStorageID());
+        MacSet *ms = FlowGetStorageById(f, MacSetGetFlowStorageID());
         if (ms != NULL && MacSetSize(ms) > 0) {
             jb_open_object(js, "ether");
             JSONMACAddrInfo info;