revised r29314
	- adapted Open MPI version check (the "const" stuff will come with version 1.7.4, not from 1.9.0)
	- removed the const keyword from the deprecated functions MPI_Type_hindexed and MPI_Type_struct
	  TODO: Since MPICH v3.x adds the const keyword to that functions we need a configure test to figure out whether adding const is required. (only relevant for the stand-alone version of VampirTrace)