Fixed out-of-range colour component value

The value "6" was probably meant to be "0.6",
as it seems HSV ranges should be 0 to 1.

Fixes undefined cast of large double to uint8
found by clang's ubsan.

Change-Id: I18120efe1638e2c175e8ba439941b7023f906a65
Merge topic 'otherColorTransferFunction-fix' into master

c3ab58e4 Fixed out-of-range colour component value