[Tagging] Fire hydrants vs suction_point

[marc marc]

>     The simplest (and in many case the only) way to tranfser hydrants
>     attributes to GPS is to put them in waypoints names.

you can also just use the same as you did in the past, as you do not use 
the name of the osm tag anyway

> For sake of simplicity, fire_hydrant: and suction_point namespaces 
> should be avoided as done for fire_hydrant:position

fire_hydrant:flow_capacity could also just be the already existing key 
flow_capacity