/usr/lib/x86_64-linux-gnu/libOgreTerrain.so is in libogre-dev 1.7.4+dfsg1-7.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libOgreTerrain.so.1.7.4
/usr/lib/x86_64-linux-gnu/libOgreTerrain.so.1.7.4