webdav: Do not throw when saving new document.

Propagate information about !shouldAccessNetworkAfterException
from getResourceType out to getPropertyValues, to avoid further calls
which would result in cancelCommandExecution, when trying get properties
of document which does not exist yet, but we want to create it.

This was done in webdav-neon for other reasons as part of
0c3500115c4fd86284a027fc32be704afcf77061.

Change-Id: Ia434a707d2946a6982075f9bf53904b78dc07a5e
(cherry picked from commit 96e23564e95d2ecc5483e55b022c8a4db04d116b)
Reviewed-on: https://gerrit.libreoffice.org/9888
Reviewed-by: Michael Stahl <mstahl@redhat.com>
Tested-by: Michael Stahl <mstahl@redhat.com>