camel log component: logger from registry

Hiya

There seems to be a little inconsistency between the log component and the
log DSL

Log component documentation says that it will always use a logger from the
registry if a one is found

Log DSL documentation says that it will only use a logger from the registry
if the logger is not specified

In fact, I think the log DSL behaviour is best since you can override the
registry with the logger in the EIP parameters. At the moment I need to use
the log component, but some other code has its own logger in the registry,
so I have to either define a logger in the registry and refer to it in the
URI, or define a second one and not refer to it (multiple loggers in
regsitry forces log component to use configured URI)

thanks!