A non-zero return value from heim_config_parse_debug() means there
was an failure to open or parse the configuration data. However, it
is not necessarily an error code. Callers when setting an error
message must use an error code.
This change to heim_config_parse_file_multi() and
heim_config_parse_string_multi() set an error code of
HEIM_ERR_CONFIG_BADFORMAT when setting the error message.
Change-Id: I534b9af1c50e32d79799a936cb6252dab99c2a64