Fix to water filter where there was a remaining "m_" in a paremeter set

Thanks to maximusgrey 

git-svn-id: https://jmonkeyengine.googlecode.com/svn/trunk@10780 75d07b2b-3a1a-0410-a2c5-0572b91ccdca

engine/src/core-effects/com/jme3/water/WaterFilter.java

@@ -1024,7 +1024,7 @@ public class WaterFilter extends Filter {
     public void setReflectionDisplace(float reflectionDisplace) {
         this.reflectionDisplace = reflectionDisplace;
         if (material != null) {
-            material.setFloat("m_ReflectionDisplace", reflectionDisplace);
+            material.setFloat("ReflectionDisplace", reflectionDisplace);
         }
     }