Fixed warning when trying to find a srgb format for a Depth format.

jme3-core/src/main/java/com/jme3/renderer/opengl/TextureUtil.java

@@ -90,6 +90,8 @@ final class TextureUtil {
     }
 
     public GLImageFormat getImageFormatWithError(Format fmt, boolean isSrgb) {
+        //if the passed format is one kind of depth there isno point in getting the srgb format;
+        isSrgb = isSrgb && fmt != Format.Depth && fmt != Format.Depth16 && fmt != Format.Depth24 && fmt != Format.Depth24Stencil8 && fmt != Format.Depth32 && fmt != Format.Depth32F;
         GLImageFormat glFmt = getImageFormat(fmt, isSrgb);
         if (glFmt == null && isSrgb) {
             glFmt = getImageFormat(fmt, false);