Skip indexing PCAWG excluded donors by using new metadata JSONL file

[junjun-zhang]

To reflect correct PCAWG datasets associated publication, data files belonging to PCAWG excluded donors should not be indexed. Previous issue: icgc-dcc/dcc-portal#524

The repository indexer currently uses a JSONL file to retrieve PCAWG metadata information, this file is pulled from http://pancancer.info/data_releases/latest/release_may2016.v1.4.with_consensus_calls.jsonl

The DCC bioinfo team has created a new JSONL file with PCAWG excluded donors removed: http://pancancer.info/data_releases/latest/release_may2016.v1.4.with_consensus_calls.excluded_donors_removed.jsonl

Switching to the new JSONL should get us the desired index.

This needs to be tested thoroughly, there could be unintended side affect when some PCAWG donors removed from the JSONL. The DCC Bioinfo team can help with testing and investigating if things break unexpectedly.