v0.15.17-hotfix.1

Changelog

This hotfix release allows for earlier access for end users on 0.15.17 to high volume query improvements.

Performance

• M3DB: Add index regexp DFA compilation cache to avoid allocating DFAs for same expressions (#2814)
• M3DB: Use false as default value for cache on retrieve to rely on FS cache in favor of expensive cache allocated by Go runtime (#2813)