LibreOffice creates .~lock files which prevent the access to the Document from loviewer

[Stefano Verzegnassi]

When docviewer loads a document through loviewer, a file called '.~lock.<file_name>#' is created in order to grant that only one LibreOffice client at a time can access to the document.

This 'lock' file seems not to be deleted when we close DocViewer (or libreofficekit don't handle them at all, don't know yet), and there's an high probability we can not open the same document again.

Since we only provide a viewer (no edit feature has been implemented yet), we can workaround this by disabling the file locking feature in LibreOffice.

[Jenkins Bot (ubuntu-core-apps-jenkins-bot)]

Fix committed into lp:ubuntu-docviewer-app/reboot at revision 196, scheduled for release in ubuntu-docviewer-app, milestone Unknown