Refs #101003  Clarify the mmap failure warning, and only give it in the null output case.
Refs #101003  Clarify the mmap failure warning, and only give it in the null output case.

svartika/ccnx,svartika/ccnx,svartika/ccnx,svartika/ccnx,svartika/ccnx,svartika/ccnx,svartika/ccnx