Fix configure & make build with python disabled

This makes sure that nothing that requires Python is being built
when the LLDB_DISABLE_PYTHON flag is being passed in.
It also changes a use of CPPFLAGS to CPP.Flags since the former is overridden
when external flags are passed in while the later is not. I'm not sure exactly
why LLDB_DISABLE_PYTHON is in CXXFLAGS rather than CPPFLAGS,
but cleaning that up is for another commit.

Differential Revision: http://reviews.llvm.org/D4918