GoXDCR: No errors recorded in goxdcr.log/UI when replication is incomplete

Build
------
4.0.0-1685

Clearly dcp has not sent the keys goxdcr has requested for. Errors[] is empty.
So no errors are shown on GUI either.

In some such cases, I see "Xmem is stuck", but looks like not all code paths are covered.

StatisticsManager2015/03/27 15:38:58.295353 [INFO] total_doc=3563450, docs_processed=0, changes_left=3563450
StatisticsManager2015/03/27 15:38:58.295858 [INFO] Stats for pipeline 82a2f20fa1a1174280f5038315b5a6f3/default/default-163977362 {"CkptMgr": {"num_checkpoints": 0, "num_failedckpts": 0, "time_committing": {"count": 0, "max": 0, "mean": 0, "min": 0}}, "Errors": "[]", "Overview":

{"bandwidth_usage": 0, "changes_left": 3563450, "data_replicated": 0, "docs_checked": 0, "docs_failed_cr_source": 0, "docs_filtered": 0, "docs_opt_repd": 0, "docs_processed": 0, "docs_received_from_dcp": 0, "docs_rep_queue": 0, "docs_written": 0, "num_checkpoints": 0, "num_failedckpts": 0, "rate_doc_checks": 0, "rate_doc_opt_repd": 0, "rate_received_from_dcp": 0, "rate_replicated": 0, "size_rep_queue": 0, "time_committing": 0, "wtavg_docs_latency": 0, "wtavg_meta_latency": 0}

, "Progress": "Pipeline is running", "Status": "Replicating", "XDCRRouter":

{"docs_filtered": 0}

, "dcp_82a2f20fa1a1174280f5038315b5a6f3/default/default_127.0.0.1:11210_0":

{"docs_received_from_dcp": 0}

, "dcp_82a2f20fa1a1174280f5038315b5a6f3/default/default_127.0.0.1:11210_1":

{"docs_received_from_dcp": 0}

, "xmem_82a2f20fa1a1174280f5038315b5a6f3/default/default_10.3.4.188:11210_0":

{"data_replicated": 0, "docs_failed_cr_source": 0, "docs_opt_repd": 0, "docs_rep_queue": 0, "docs_written": 0, "size_rep_queue": 0}

, "xmem_82a2f20fa1a1174280f5038315b5a6f3/default/default_10.3.4.188:11210_1": {"data_replicated": 0, "docs_failed_cr_source": 0, "docs_opt_repd": 0, "docs_rep_queue": 0, "docs_written": 0, "size_rep_queue": 0}}

StatisticsManager2015/03/27 15:38:58.295966 [INFO] Xmem xmem_82a2f20fa1a1174280f5038315b5a6f3/default/default_10.3.4.188:11210_0 state =2 connType=MemConn received 0 items, sent 0 items, 0 items waiting to confirm, 0 in queue
StatisticsManager2015/03/27 15:38:58.296025 [INFO] Xmem xmem_82a2f20fa1a1174280f5038315b5a6f3/default/default_10.3.4.188:11210_1 state =2 connType=MemConn received 0 items, sent 0 items, 0 items waiting to confirm, 0 in queue
StatisticsManager2015/03/27 15:38:58.296085 [INFO] Rounter Router_dcp_82a2f20fa1a1174280f5038315b5a6f3/default/default_127.0.0.1:11210_0 = map[xmem_82a2f20fa1a1174280f5038315b5a6f3/default/default_10.3.4.188:11210_0:0]
StatisticsManager2015/03/27 15:38:58.296171 [INFO] Dcp dcp_82a2f20fa1a1174280f5038315b5a6f3/default/default_127.0.0.1:11210_0 streamed 0 items. [] streams inactive
StatisticsManager2015/03/27 15:38:58.296229 [INFO] Rounter Router_dcp_82a2f20fa1a1174280f5038315b5a6f3/default/default_127.0.0.1:11210_1 = map[xmem_82a2f20fa1a1174280f5038315b5a6f3/default/default_10.3.4.188:11210_1:0]
StatisticsManager2015/03/27 15:38:58.296310 [INFO] Dcp dcp_82a2f20fa1a1174280f5038315b5a6f3/default/default_127.0.0.1:11210_1 streamed 0 items. [] streams inactive

Will attach goxdcr log from the node.