[system test] Indexer Panic due to No Valid Restart Seqno

0.Cluster has unhealthy indexes - either the indexes are timing out, or showing "stale metadata" errors.

• To start over, I decided to drop the indexes - which fails with GSI scan timeout
• I restarted the indexer, hoping things work - No progress, same errors.
• To still make this work, I decided to delete the index files from its directory
  storageDir=/index/@2i
  rm -rf /index/@2i

Expectation - The cluster should have no indexes.
Restarting the indexer and projector - should get the cluster back to some workable state.

This did not work - I assume this is not supported?

The indexer logs now contain panic on "no valid seq no"
also, the Node is down and unusable.

Filing this is a "major" bug to know what caused the indexer to crash.

logs from indexer node https://s3.amazonaws.com/bugdb/bug_index/10_167_2.tar