Instead of making all chart objects exempt from unloading, check each OLE
object on whether or not it already has its persistent storage created.
If not, don't unload it else it would have nothing to load back from once
unloaded.

(cherry picked from commit a0bd5587)

Conflicts:
	svx/source/svdraw/svdetc.cxx
	embeddedobj/source/commonembedding/miscobj.cxx
	embeddedobj/source/commonembedding/persistence.cxx
	include/svx/svdoole2.hxx
	svx/source/svdraw/svdoole2.cxx

Change-Id: I2312e86c9376d3699ef4aa1e0cf2f4c04f706c1e