Honor --initial after a crash

[renecannao]

If you are submitting a reproducible bug report, please provide:

• A clear description of the issue

--initial is ignored after a crash.
This is by design: --initial just cause the rename of proxysql.db during the initial start.
Although it seems reasonable that after a crash the same logic is implemented.

• ProxySQL version

All up to latest (2.7.0)

• OS version

All

• The steps to reproduce the issue

• start proxysql in background , with --initial
• update the config file
• crash it (kill it with -6 or -9)
• proxysql will now have outdated configuration

• Possible solution
  Rename logic (see https://github.com/sysown/proxysql/blob/v2.7.0/src/main.cpp#L715-L720) should be implemented also during restart in https://github.com/sysown/proxysql/blob/v2.7.0/src/main.cpp#L1469-L1478