phosphor-mapper: Drop blacklist feature

An interface and path blacklisting feature was implemented in the
python mapper but it isn't used, and it wasn't implemented in the
c++ mapper.  Drop support to make a small improvement to
comprehensional complexity and ease the transition to the c++ mapper.

(From meta-phosphor rev: 6b10fd583d7c1baed14f6076322548f4f097d9db)

Change-Id: I3346f1929689b75553b8331a6ac1b5df0d5c87cb
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>