cmake: set soversion for libs, such that ocl finds it.
cmake: set soversion for libs, such that ocl finds it.

Signed-off-by: Peter Soetens <4b8373d016f277527198385ba72fda0feb5da015@thesourceworks.com>

orocos-toolchain/log4cpp,phamelin/orocos-log4cpp,phamelin/orocos-log4cpp,phamelin/orocos-log4cpp,phamelin/orocos-log4cpp,orocos-toolchain/log4cpp