Fix incorrect results from evbuffer_search_eol(EOL_LF) Our evbuffer_strchr() function [which was only used for search_eol(EOL_LF) could give incorrect results if it found its answer in the first chunk but didn't start searching from the front of the chunk. Also, this patch adds unit tests for evbuffer_search_eol, particularly in those cases that evbuffer_readln() tests didn't exercise.