On Gerrit fix for tdf#95272: Lock missing when saving a file (save as) on some webdav server

Hi all,

the fix for subj bug:
<https://bugs.documentfoundation.org/show_bug.cgi?id=95792>
is here:
<https://gerrit.libreoffice.org/#/c/20600/>
This is the commit comment, should explain all:
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tdf#95792: fix saving file the first time on some WebDAV servers.

Some WebDAV servers don't implement section 7.3 of RFC4918:
<http://tools.ietf.org/html/rfc4918#section-7.3>

This lack of implementation breaks 'Save As...' functionality
when the target is a WebDAV server, by not locking the URL
('reserve the name for use', in RFC4918 parlance).

The server not implementing this usually answers with one of
'405 Method Not Allowed', '501 Not Implemented' or
'412 Precondition Failed' http error codes.

The fix should manage this lack of implementation.
------------------

The fix adds a few lines to sfx2, issuing another lock command after the 
file has been saved.

Reviewers are welcome.

Thanks.

--
Kind Regards,
Giuseppe Castagno aka beppec56
Acca Esse http://www.acca-esse.eu
giuseppe.castagno at acca-esse.eu