refresh relayFilter after relay changed

[mikewuhao]

If a client is configed to pull data from multi relays and these relays has diffrent id-source relationship,the client' partition thread may pull all partition's data from relay.That's because the _relayFilter property can't be refreshed after client change relay. For example:

1. there are two relays RA and RB.
   2.RA and RB conern one table T , but has diffrent id-source relation.RA's source config is:
   id:1,
   source:test.T
   RB's source config is:
   id:2,
   source:test.T
2. A client is configerd to pull data from RA and RB
   4.client pull data from RA and the stream request's filter params looks like this:
   {"1":{"partitionType":"MOD","filters":[{"bktRange":{"start":0,"end":1},"numBuckets":10}]}}
3. when client start to pull data from RB, the filter params will not be changed.but RB don't have the source-id 1 table.RB will return all data without server side filter.

[buptyzc]

good