fdo#44831: Named range should overwrite existing name.

When inserting a new named range, it should overwrite any existing
name if one exists.  That was the old behavior in 3.3 prior to my
range name rework, and because of ptr_map not overwriting existing
key, that behavior had changed unintentionally.

Let's revert to the old behavior.

sc/inc/rangenam.hxx

@@ -222,7 +222,7 @@ public:
     SC_DLLPUBLIC size_t size() const;
     bool empty() const;
 
-    /** Insert object into set if not a duplicate.
+    /** Insert object into set.
         @ATTENTION: The underlying ::boost::ptr_set_adapter::insert(p) takes
         ownership of p and if it can't insert it deletes the object! So, if
         this insert here returns false the object where p pointed to is gone!

sc/source/core/tool/rangenam.cxx

@@ -894,6 +894,7 @@ bool ScRangeName::insert(ScRangeData* p)
     }
 
     rtl::OUString aName(p->GetUpperName());
+    maData.erase(aName); // ptr_map won't insert it if a duplicate name exists.
     pair<DataType::iterator, bool> r = maData.insert(aName, p);
     if (r.second)
     {