zpaq: fix building to depend on ENABLE_ZPAQ, not ENABLE_SHARC

Signed-off-by: Evan Nemerson <evan@coeus-group.com>
fari: disable FARI plugin since it is not reliable

See https://github.com/davidcatt/FastARI/issues/2

Signed-off-by: Evan Nemerson <evan@coeus-group.com>