rsl_remove_volume

 This procedure removes a volume from the radar structure.

 Syntax
     rsl_remove_volume, radar, volspec [, ERROR=variable]

 Arguments
    radar:   radar structure.  It is modified by this procedure.
    volspec: either a field name or volume index indicating the volume to be
             removed.

 Keywords
    ERROR:   set this keyword to a variable to return error flag:
             0 for no error, 1 for error.