Removes deprecated usage of BaseException.message

Reasons:
- util\mysql.py is using deprecated BaseException.message
- message pops up in integration tests logs too.

Changes:
- Fixed the warning messages during tests.

Change-Id: I8bfe1cb8b1755d5481eda8d0b660340b04d2a171
Closes-Bug: #1267201
Merge "Removes deprecated usage of BaseException.message"