75d0e4c544 [qa] Delete cookie file before starting node (Suhas Daftuar)
Pull request description:
When a node is restarted during a test after an unclean shutdown (such
as with -dbcrashratio), it's possible an old cookie file was left
behind. This can cause a race condition when restarting the node, where
the test framework might try to connect using credentials from the
old cookie file, just as the node will generate new credentials and
overwrite the old file.
Delete any such cookie file if present prior to startup.
Tree-SHA512: ae1e8bf8fd20e07c32b0715025693bb28b0e3dd34f328cae4346abf579b0c97b5db1c02782e1c46b7a3b6058d268b6d46b668e847658a6eed0be857ffb0d65dc
727175a08d