Steps to reproduce:

1. Set up your connector to stream item values, with an and/or tag "foo" equals "bar"
2. Pick any item with history being retained and tag it with "foo" equals "bar"
3. Observe that the item's history values are sent to your connector endpoint
   Set the item from step 2 to history: do not store
4. Observe that the item's history values cease to be sent to your connector endpoint

Result:
Item values are neither stored in the database nor forwarded to the connector.

Expected:
Item values are forwarded to the connector but not stored in the database.

History values seem to be getting dropped in `DCexport_history()` in `src/libs/zbxcachehistory/cachehistory.c` because ZBX_DC_FLAG_NOHISTORY is set. I've attached a patch which changes this behavior to what I expected.

Is this a bug, or is this the intended behavior? If it's the intended behavior, can an override be added to the connector or item in order to send item values even when history isn't kept?

Thanks,

John