Total hack, but this just worked. We still need a clean way of uninstalling opencv2.4
$ opkg list | grep opencv
$ opkg remove lib32-opencv --force-removal-of-dependent-packages
$ opkg list | grep opencv
$ opkg remove lib32-opencv-dbg --force-removal-of-dependent-packages
$ opkg remove lib32-opencv-calib3d2.4 --force-removal-of-dependent-packages
$ opkg list | grep opencv
$ opkg remove lib32-libopencv-calib3d2.4 --force-removal-of-dependent-packages
$ opkg list | grep opencv
$ opkg remove lib32-libopencv-core2.4 --force-removal-of-dependent-packages
$ opkg install opencv_3.4.6_8x96.ipk
$ /usr/bin/opencv_version
3.4.6