/usr/lib/x86_64-linux-gnu/libOSMesa16.so is in libosmesa6-dev 8.0.5-4+deb7u2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libOSMesa16.so.6
/usr/lib/x86_64-linux-gnu/libOSMesa16.so.6