Update DRIVER_NAME string to match what's used in 4.x

patch by Bret McGuire; reviewed by Bret McGuire, Andy Tolbert for CASSJAVA-58

Author: absurdfarce

driver-core/src/main/java/com/datastax/driver/core/Requests.java

@@ -45,6 +45,7 @@ static class Startup extends Message.Request {
     private static final String DRIVER_VERSION_OPTION = "DRIVER_VERSION";
     private static final String DRIVER_NAME_OPTION = "DRIVER_NAME";
     private static final String DRIVER_NAME = "ScyllaDB Java Driver";
+    private static final String DRIVER_NAME = "ScyllaDB Java Driver";
 
     static final String COMPRESSION_OPTION = "COMPRESSION";
     static final String NO_COMPACT_OPTION = "NO_COMPACT";