[Cin] disable a_key in blur.C harder

[Andrew Randrianasulu]

At this point I am not sure if best course of action to disable it harder
or restore it ...

but I hope attached patch at least visually restores strange mess we see by
default now in test project.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.cinelerra-gg.org/pipermail/cin/attachments/20240226/330cc326/attachment.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 0001-TEST-disable-blur-alpha-determinates-radius-harder.patch
Type: text/x-diff
Size: 1416 bytes
Desc: not available
URL: <https://lists.cinelerra-gg.org/pipermail/cin/attachments/20240226/330cc326/attachment.bin>