remove unused regular expression in parse_extra() in tabcreatedb.py

This regular expression would not work with Python3 anymore.
But it is not used anyway, so it can be just removed.
Remove unused function add_new_phrases()
Return only tabkeylist in parse_phrase()

The other stuff returned is never used, just thrown away.
Remove unused code
Do not fail when the environment variable HOME is not set

Resolves: rhbz#1088138 - [abrt] ibus-table: posixpath.py:83:join:TypeError: unsupported operand type(s) for +=: 'NoneType' and 'str'
See: https://bugzilla.redhat.com/show_bug.cgi?id=1088138
Merge pull request #33 from mike-fabian/do-not-fail-when-home-is-not-set

Do not fail when home is not set