Switches from STR_SVT_FILEPICKER_ to STR_FPICKER_ resource IDs and
uses the default resource manager (ImplGetResMgr).

The STR_FPICKER_ IDs contain default translated titles for the open
and save dialogs, which KDE4 dialogs are currently missing.

Actually I want 'Save as' instead of 'Save'... but it's better
then the current - empty - default.

Change-Id: Ia43774ea66a96838f53cf6614a264d9c6a94c501