fix tests in error

fix:
{code}
Tests in error: 
  initializationError(InjectedTest): com.sun.jna.Native.open(Ljava/lang/String;)J
  initializationError(hudson.plugins.performance.PerformancePublisherTest): org.jvnet.hudson.test.HudsonTestCase
{code}
Merge pull request #20 from tomaszuss/patch-1

thanks