Add flag to prevent mysql db start up failure

MySQL version 5.7 contains a bug that prevents start up when there are
files in the lost+found directory (which appear to get created on start
up). This issue only appears to affect the AWS deployment...
See link below for details

OHM-972
docker-library/mysql#186 (comment)

core/kubernetes/main/hapi-fhir/hapi-fhir-mysql-deployment.yaml

@@ -17,6 +17,8 @@ spec:
       containers:
         - name: hapi-fhir-mysql
           image: mysql:5.7
+          args:
+            - '--ignore-db-dir=lost+found'
           env:
             - name: MYSQL_DATABASE
               value: hapi