(POOLER-133) Identify when a ready VM has failed

This commit fixes checking of a VM that has already been identified as ready. Without this change a ready VM that has failed will be identified as having failed, but will not successfully be removed from the ready queue. Additionally, the default vm_checktime value has been reduced from 15 to 1 to ensure that ready VMs are checked within one minute of the time they have reached the ready state by default.

Lastly, the docker-compose files are updated to specify that the redis
instance used is a local redis instance.

docker/docker-compose.yml

@@ -16,11 +16,11 @@ services:
     environment:
       - VMPOOLER_DEBUG=true # for use of dummy auth
       - VMPOOLER_CONFIG_FILE=/etc/vmpooler/vmpooler.yaml
-      - REDIS_SERVER=redis
+      - REDIS_SERVER=redislocal
     image: vmpooler-local
     depends_on:
-      - redis
-  redis:
+      - redislocal
+  redislocal:
     image: redis
     ports:
       - "6379:6379"