Py3: Cleanup test_mail-alarm.py to use python3 test helpers an move it

[ashwin9390]

This PR contains the following changes,

• Update test_mail-alarm.py to test with Python3
• Move the test to the python3/tests directory
• Replace the old method of copying the script to a temp directory and importing it as a module with the import_helper module from python3/tests
• Remove the use of another temporary file to gather logged errors
• Remove the obsolete nottest decorator
• The test is now run against the Python3 version of mail-alarm
• The test was also run against the original Python2 mail-alarm during the update, but this PR only updates the test for Python3
• After this PR, there are no longer any Python2 tests left

Author :Bernhard Kaindl [email protected]
Committed by :Ashwinh [email protected]

[bernhardkaindl]

As described: Uses the new infrastructure for imports and cleans up the obsoleted code.