Remove config.Config from tempdir package

Usage of the global config.Config variable replaced with the locally created value.

The order of the calls changed in the TestCleanTempDir test as it started to create additional log entry about git binary used for the test, because configuration of that happen after log level change. By switching the order the old log level is used to write that additional message and we have a new level for the cleanTempDir function call.

Part of: #2699 (closed)