Cleanup derby home dir

[MonkeyCanCode]

Description

This will cleanup derby home dir for regtest/setup.sh.

Fixes 217

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• Documentation update
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Manually corrupted the derby home dir after a successful run. After derby home got corrupted, user won't be able to rerun the script until derby home is getting cleanup. With this fix, it will cleanup the derby home dir before running the script.

Please delete options that are not relevant.

• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• If adding new functionality, I have discussed my implementation with the community using the linked GitHub issue

[flyrain]

Thanks @MonkeyCanCode for the change.