Remove bare exceptions

[Solomon1732]

Remove bare exceptions. Also refractored %-format to f-strings. Closes #33

[tribler-ci]

Can one of the admins verify this patch?

[devos50]

ok to test

[devos50]

======================================================================
ERROR: Failure: SyntaxError (invalid syntax (util.py, line 102))
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/nose/failure.py", line 39, in runTest
    raise self.exc_val.with_traceback(self.tb)
  File "/usr/lib/python3/dist-packages/nose/loader.py", line 417, in loadTestsFromName
    addr.filename, addr.module)
  File "/usr/lib/python3/dist-packages/nose/importer.py", line 47, in importFromPath
    return self.importFromDir(dir_path, fqname)
  File "/usr/lib/python3/dist-packages/nose/importer.py", line 94, in importFromDir
    mod = load_module(part_fqname, fh, filename, desc)
  File "/usr/lib/python3.7/imp.py", line 234, in load_module
    return load_source(name, filename, file)
  File "/usr/lib/python3.7/imp.py", line 171, in load_source
    module = _load(spec)
  File "<frozen importlib._bootstrap>", line 696, in _load
  File "<frozen importlib._bootstrap>", line 677, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 728, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "/home/jenkins/ci/workspace/AnyDex/test_anydex_PR_linux/anydex/test/core/test_block.py", line 11, in <module>
    from anydex.test.base import BaseTestCase
  File "/home/jenkins/ci/workspace/AnyDex/test_anydex_PR_linux/anydex/test/base.py", line 11, in <module>
    from anydex.test.util import process_unhandled_asyncio_exceptions, process_unhandled_exceptions
  File "/home/jenkins/ci/workspace/AnyDex/test_anydex_PR_linux/anydex/test/util.py", line 102
    class MockObject(object):
        ^
SyntaxError: invalid syntax