Remove no longer used JavaCrypt

Author: enebo

core/src/main/java/org/jruby/RubyString.java

@@ -65,7 +65,6 @@
 import org.jruby.runtime.encoding.MarshalEncoding;
 import org.jruby.runtime.marshal.UnmarshalStream;
 import org.jruby.util.ByteList;
-import org.jruby.util.encoding.Transcoder;
 import org.jruby.util.ConvertBytes;
 import org.jruby.util.Numeric;
 import org.jruby.util.Pack;
@@ -75,9 +74,7 @@
 import org.jruby.util.Sprintf;
 import org.jruby.util.StringSupport;
 import org.jruby.util.TypeConverter;
-import org.jruby.util.string.JavaCrypt;
 
-import java.io.UnsupportedEncodingException;
 import java.nio.charset.Charset;
 import java.util.Locale;