Missing launch of FactoryLoader threads

...regression introduced with 06a09dd0 "Join
FactoryLoader threads."  (Also, hopefully, the original use of
osl::Thread::setPriority was just cargo cult, as salhelper::Thread does not make
that feature available to clients, so it had been dropped in
06a09dd0.)

Change-Id: I055c8fb20f3bbf13ba823436be24167d3446ed05

reportdesign/source/core/api/ReportDefinition.cxx

@@ -726,8 +726,9 @@ void OReportDefinition::init()
             const OUString* pEnd  = pIter + aMimeTypes.getLength();
             for ( ; pIter != pEnd; ++pIter )
             {
-                m_pImpl->m_aFactoryLoaders.push_back(
-                    new FactoryLoader(*pIter,m_aProps->m_xContext));
+                rtl::Reference<salhelper::Thread> xCreatorThread = new FactoryLoader(*pIter,m_aProps->m_xContext);
+                m_pImpl->m_aFactoryLoaders.push_back(xCreatorThread);
+                xCreatorThread->launch();
             }
         }