Fix typo in tests/meta/CMakeLists.txt
Fix typo in tests/meta/CMakeLists.txt

The condition should be ```IF (EXISTS <FileName>)``` or ```IF (EXISTS <DirName>/)```.
Missing the trailing ```/``` will return FALSE for dir.
sorig/shogun,sorig/shogun,shogun-toolbox/shogun,sorig/shogun,shogun-toolbox/shogun,besser82/shogun,besser82/shogun,karlnapf/shogun,shogun-toolbox/shogun,besser82/shogun,karlnapf/shogun,lisitsyn/shogun,geektoni/shogun,karlnapf/shogun,lisitsyn/shogun,geektoni/shogun,lambday/shogun,lisitsyn/shogun,lambday/shogun,shogun-toolbox/shogun,sorig/shogun,lambday/shogun,lambday/shogun,shogun-toolbox/shogun,karlnapf/shogun,sorig/shogun,lisitsyn/shogun,geektoni/shogun,geektoni/shogun,shogun-toolbox/shogun,geektoni/shogun,lisitsyn/shogun,karlnapf/shogun,lisitsyn/shogun,besser82/shogun,besser82/shogun,lambday/shogun,geektoni/shogun,besser82/shogun,sorig/shogun,karlnapf/shogun,lambday/shogun