C++: [skip ci] fix -Wredundant-move

This change was part of #2720 but has been skipped in order to not complicate a pending PR of an upgrade of the SMESH sources.
However, this other PR #2706 has been closed by its author.
Since this warning is reported on latest Fedora version using gcc 10 it will be fixed now.

src/3rdParty/salomesmesh/src/SMESH/GEOMUtils.cpp

@@ -643,7 +643,7 @@ TopoDS_Shape GEOMUtils::CompsolidToCompound (const TopoDS_Shape& theCompsolid)
     }
   }
 
-  return std::move(aCompound);
+  return TopoDS_Shape(std::move(aCompound));
 }
 
 //=======================================================================

src/3rdParty/salomesmesh/src/SMESH/SMESH_subMesh.cpp

@@ -2100,7 +2100,7 @@ TopoDS_Shape SMESH_subMesh::getCollection(SMESH_Gen * theGen,
     }
   }
 
-  return std::move(aCompound);
+  return TopoDS_Compound(std::move(aCompound));
 }
 
 //=======================================================================