WaE: format string is not a string literal (potentially insecure)

(cherry picked from commit 765cd0ebaabf9cf7948ae1424681de144c7d267e)
Signed-off-by: Tor Lillqvist <tml@collabora.com>

Change-Id: I568817c33aa555bc8aef93105e6a00be1d4b501d
Reviewed-on: https://gerrit.libreoffice.org/8753
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>