Fix problems with very long filenames in both smbd and smbclient.

Fix problems with very long filenames in both smbd and smbclient.
It appears that we pass filename through resolve_wildcards() as pstring and use fstring temporary buffer there.
As result, a long filename in unix charset (UTF-8 by default) can easily expand over 255 bytes while
Windows is able to send to us such names (e.g. Japanese name of ~190 mb chars) which we unable to process through
this small fstring buffer. Tested with W2K and smbclient, Japanese and Cyrillics.
(This used to be commit cc70a548f3c48a9503fd54d01896cc2499f5bbcd)