variable's range is not respected when created through config_ChainParse

This is the equivalent of the below linked ticket, the difference of course being that the problem occurs if the variable is created through config_ChainParse.

= #17430 (closed) =	variable's range is not respected when created through command-line

The observed behavior is the same, but given that there are different paths leading up to the problem (and therefor several different options to fixing one/both) two tickets has been created.

testcase

vlc-trunk drop.avi '--sout=#transcode{vcodec=mp4v,vfilter=croppadd{croptop=-100}}:display' vlc://quit -q -Idummy