fixed wrong class name generation for fixed length strings

Author: pavlobaron

main/java/uk/co/real_logic/sbe/generation/java/JavaGenerator.java

@@ -982,7 +982,7 @@ private CharSequence generateArrayProperty(
  indent + " CodecUtil.charsPut(buffer, this.offset + %d, src, srcOffset, length);\n" +
  indent + " return this;\n" +
  indent + " }\n",
- containingClassName,
+ formatClassName(containingClassName),
  toUpperFirstChar(propertyName),
  fieldLength,
  offset