updated spotbug issue

Author: nikhilbhoski

src/main/java/com/mathworks/ci/RunMatlabTestsBuilder.java

@@ -41,7 +41,6 @@
 public class RunMatlabTestsBuilder extends Builder implements SimpleBuildStep, MatlabBuild {
 
     private int buildResult;
-    private EnvVars env;
 
     // Make all old values transient which protects them writing back on disk.
     private transient boolean tapChkBx;