Add comment about why execution dep is disabled
Add comment about why execution dep is disabled

such reason (cyclic dependency with query) wasn't in the commit
associated to that disabling either so...

AmeBel/atomspace,AmeBel/atomspace,AmeBel/atomspace,rTreutlein/atomspace,rTreutlein/atomspace,AmeBel/atomspace,rTreutlein/atomspace,rTreutlein/atomspace,rTreutlein/atomspace,AmeBel/atomspace