Fix issue with DB losing connection and app dying.

[dialmaster]

This happens about once every ~ 5-6 days. We need to investigate why and stop it from happening:

[GIN] 2022/02/04 - 06:03:16 | 200 | 7.650635ms | 68.186.0.45 | GET "/getminingstats" Current block height from node: 1190978 [mysql] 2022/02/04 06:03:17 packets.go:123: closing bad idle connection: EOF panic: dial tcp 127.0.0.1:3306: connect: connection refused goroutine 16 [running]: main.getDBHeight() /home/ubuntu/dmo-statservice/main.go:105 +0x105 main.updateStats() /home/ubuntu/dmo-statservice/main.go:199 +0xd1 main.main.func1()