Add OH dependance to HFC lifetimes

[ssmithClimate]

The sink for HFCs and HCFCs (but not PFCs, SF6, etc.) are also oxidation in the atmosphere. OH will also impact lifetimes here and should be added.

Also, looks like the "HFC component" applies to gases other than HFCs. Perhaps re-name to F-gas component.

[rgieseke]

There are also CH3CCl3_halocarbon and CCl4_halocarbon, aren't they?