check_patch.py: Catch exceptions during pylint run

pylint (or some of the dependent libraries) also has
bugs, so when they happen we don't want to spoil our
entire run. Let's catch the exceptions and report them.

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>
tools/check_patch.py: Exclude files from check only on old python

We do all possible to run static checking of modules
on older python, given that it is easier to spot
python 2.4 non compliances. However, we have a bunch
of quirks with files on older python. Therefore, let's
skip certain files from the checks if running under
py < 2.5.

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>