Strip filter name from command before passing to filter function. The new registration of in-process data filters (introduced in f8ad3b76e923 & 11af38a592ae) failed to correctly strip the filter name from its arguments before passing the "command" to the filter function. Thus a registration such as [decode] *.gz = compress: -9 would result in the associated filter function being called with the argument 'compress: -9' rather than just '-9' as expected.