Checking the path is set is not enough, we should also check the path
exists. This allows people to have a general-purpose
.ycm_extra_conf.conf that automatically loads a database file if exists,
and falls back to the manual flags if not.
ycm_extra_conf.py files used to import clang_helpers and then use the
PrepareClangFlags function; this is now unnecessary since the logic from that
function has been moved to flags.py. The old PrepareClangFlags function is still
there (it just returns the flags it gets) for the sake of backwards
compatibility with old ycm_extra_conf.py files.
It was never supposed to be licensed under the GPL since it's effectively
example code (that's also used for YCM compilation flags, but still).
No one has ever edited this file except me, Strahinja Val Markovic, and thus I
can release it into the public domain.
