Make it const
Make it const

Just like pull req #569 suggests.

AmeBel/atomspace,yantrabuddhi/atomspace,yantrabuddhi/atomspace,AmeBel/atomspace,ArvinPan/atomspace,rTreutlein/atomspace,ceefour/atomspace,inflector/atomspace,inflector/atomspace,inflector/atomspace,inflector/atomspace,ceefour/atomspace,yantrabuddhi/atomspace,ceefour/atomspace,misgeatgit/atomspace,AmeBel/atomspace,misgeatgit/atomspace,yantrabuddhi/atomspace,rTreutlein/atomspace,ArvinPan/atomspace,ArvinPan/atomspace,ceefour/atomspace,rTreutlein/atomspace,inflector/atomspace,misgeatgit/atomspace,ArvinPan/atomspace,rTreutlein/atomspace,misgeatgit/atomspace,misgeatgit/atomspace,AmeBel/atomspace,yantrabuddhi/atomspace,AmeBel/atomspace,rTreutlein/atomspace