Unify issue processing and make more robust

The issue processing in gitlog2asciidoc.py missed
certain capitilazation combinations and was split
across 2 ifs.  Combine it into one if and make it case
insensitive using an ugly python(pre 2.7) backwards
compatible method.

Change-Id: I49fb4d66bd5b3777cc9641a947730a19222895f6
1 file changed