use empty instead of size() == 0

Change-Id: I08b1e73323a15dd977daba98946e7deec3967503
Reviewed-on: https://gerrit.libreoffice.org/40575Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Markus Mohrhard <markus.mohrhard@googlemail.com>

fpicker/source/office/RemoteFilesDialog.cxx

@@ -526,7 +526,7 @@ int RemoteFilesDialog::GetSelectedServicePos()
     int nPos = 0;
     int i = -1;
 
-    if( m_aServices.size() == 0 )
+    if( m_aServices.empty() )
         return -1;
 
     while( nPos < ( int )m_aServices.size() )