Quartz Scheduler Race Condition

[nathandoef]

Describe the bug
A PSQLException is thrown when jobs are scheduled with a Quartz transactional connector and a Postgres database.

To Reproduce

1. Configure a Quartz transactional connector with a Postgres datasource
2. Start hapi-fhir and allow Quartz jobs to be scheduled
3. See error below:

ERROR: duplicate key value violates unique constraint "qrtz_locks_pkey"
  Detail: Key (sched_name, lock_name)=(cdr-scheduler-cdr-persistence, TRIGGER_ACCESS) already exists.
	at org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:2676)
	at org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:2366)
	at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:356)
	at org.postgresql.jdbc.PgStatement.executeInternal(PgStatement.java:496)
	at org.postgresql.jdbc.PgStatement.execute(PgStatement.java:413)
	at org.postgresql.jdbc.PgPreparedStatement.executeWithFlags(PgPreparedStatement.java:190)
	at org.postgresql.jdbc.PgPreparedStatement.executeUpdate(PgPreparedStatement.java:152)
	at com.mchange.v2.c3p0.impl.NewProxyPreparedStatement.executeUpdate(NewProxyPreparedStatement.java:1502)
	at org.quartz.impl.jdbcjobstore.StdRowLockSemaphore.executeSQL(StdRowLockSemaphore.java:135)

Expected behavior
Quartz jobs are scheduled with no errors