BUG/MINOR: cfgparse: parse_cfg: fix null ptr dereference reported by coverity

BUG/MINOR: cfgparse: parse_cfg: fix null ptr dereference reported by coverity

This commit fixes potential null ptr dereferences reported by coverity, see
more details about it in the issues #2676 and #2668.

'outline' ptr, which is initialized to NULL explicitly as a temporary buffer to
store split keywords may be in theory implicitly dereferenced in some corner
cases (which we haven't encountered yet with real world configurations) in
'if (!**args)'. parse_line() code, called before under some conditions
assigns: args[arg] = outline + outpos and outpos initial value is 0.