* fix data race on plugin reload
* add changelog
* add comment for posterity
* revert comment and return assignment in router.go
* rework plugin continue on error tests to use compilePlugin
* fix race condition on route entry
* add test for plugin reload and rollback race detection
* add go doc for test
* test/plugin: test external db plugin
* use test helper to get cluster and plugins
* create test helper to create a vault admin user
* add step to revoke lease
* make tests parallel and add reload test
* use more descriptive name for test group; check response
Factored out some plugin related tests into their own test package, and added a bunch of parallelism. Moved some non-plugin tests that were in logical_system_integ_test into another file (keeping them in vault package) just for cohesion.
Thy Ton