BUG/MINOR: cfgparse: report extraneous args *after* the string is allocated

BUG/MINOR: cfgparse: report extraneous args *after* the string is allocated

The config parser change in commit 9e1758efb ("BUG/MEDIUM: cfgparse: use
parse_line() to expand/unquote/unescape config lines") is wrong when
displaying the last parsed word, because it doesn't verify that the output
string was properly allocated. This may fail in two cases:
  - very first line (outline is NULL, as in oss-fuzz issue 23657)
  - much longer line than previous ones, requiring a realloc(), in which
    case the final 0 is out of the allocated space.

This patch moves the reporting after the allocation check to fix this.

No backport is needed, this is 2.2 only.