Read Nvidia Driver version via NVML

src/main/java/com/sheepit/client/os/Linux.java

@@ -49,6 +49,10 @@ public class Linux extends OS {
 		return "cuda";
 	}
 	
+	@Override public String getNVMLLib() {
+		return "nvidia-ml";
+	}
+	
 	@Override public Process exec(List<String> command, Map<String, String> env_overight) throws IOException {
 		Map<String, String> new_env = new HashMap<String, String>();
 		new_env.putAll(java.lang.System.getenv()); // clone the env