Fix #64076: imap_sort() does not return FALSE on failure

If unsupported `$search_criteria` are passed to `imap_sort()`, the
function returns an empty array, but there is also an error on the
libc-client error stack ("Unknown search criterion: UNSUPPORTED
(errflg=2)").  If, on the other hand, unsupported `$criteria` or
unsupported `$flags` are passed, the function returns `false`.  We
solve this inconsistency by returning `false` for unsupported
`$search_criteria` as well.

Closes GH-6332.

0 files changed, 0 insertions, 0 deletions