Server errors don't propagate to the client

[tebeka]

@yaronha reported that the server show the error below but the client operation ended successfully with a nil (None?) DataFrame

18.10.27 15:51:19.101 ?[37m              v3io-frames?[0m ?[34m(I)?[0m read request {"request": {"backend":"stream","schema":null,"data_format":"","row_layout":false,"multi_index":false,"query":"","table":"stockes_stream","columns":null,"filter":"","group_by":""
,"Join":null,"limit":0,"max_in_message":0,"marker":"","segments":null,"total_segment":0,"sharding_keys":null,"sort_key_range_start":"","sort_key_range_end":"","start":"now-2d","end":"","step":"","aggragators":"","seek":"time","shard":"0","sequence":140}}
18.10.27 15:51:19.265 ?[37m              v3io-frames?[0m ?[31m(E)?[0m can't query {"error": "Error in Seek operation - Failed POST with status 400"}
18.10.27 15:51:19.265 ?[37m              v3io-frames?[0m ?[31m(E)?[0m error reading {"error": "can't query: Error in Seek operation - Failed POST with status 400", "errorVerbose": "Error in Seek operation - Failed POST with status 400\ncan't query\ngithub.com/v
3io/frames/api.(*API).Read\n\tC:/Users/yaronh/go/src/github.com/v3io/frames/api/api.go:96\ngithub.com/v3io/frames/server.(*Server).handleRead.func1\n\tC:/Users/yaronh/go/src/github.com/v3io/frames/server/server.go:180\nruntime.goexit\n\tC:/Go/src/runtime/asm_am
d64.s:2361", "errorCauses": [{"error": "can't query: Error in Seek operation - Failed POST with status 400", "errorVerbose": "Error in Seek operation - Failed POST with status 400\ncan't query", "errorCauses": [{"error": "Error in Seek operation - Failed POST w
ith status 400"}]}]}