Replace OSL_ENSURE by SAL_WARN_IF + clean include

Change-Id: I4d3a50fda2f865a546aafc38f06096117da34711
Reviewed-on: https://gerrit.libreoffice.org/30588Reviewed-by: Julien Nabet <serval2412@yahoo.fr>
Tested-by: Julien Nabet <serval2412@yahoo.fr>

sfx2/source/appl/app.cxx

@@ -35,7 +35,6 @@
 #include <svl/svdde.hxx>
 #include <unotools/configmgr.hxx>
 #include <unotools/tempfile.hxx>
-#include <osl/file.hxx>
 #include <com/sun/star/lang/XInitialization.hpp>
 #include <com/sun/star/frame/XFrameActionListener.hpp>
 #include <com/sun/star/frame/XComponentLoader.hpp>
@@ -217,7 +216,7 @@ SfxApplication::SfxApplication()
 
 SfxApplication::~SfxApplication()
 {
-    OSL_ENSURE( GetObjectShells_Impl().size() == 0, "Memory leak: some object shells were not removed!" );
+    SAL_WARN_IF(GetObjectShells_Impl().size() != 0, "sfx.appl", "Memory leak: some object shells were not removed!");
 
     Broadcast( SfxHint(SFX_HINT_DYING) );