Update Charsets reference.

Author: rlubke

src/main/java/com/ning/http/client/providers/grizzly/GrizzlyAsyncHttpProvider.java

@@ -66,7 +66,7 @@
 import org.glassfish.grizzly.http.HttpResponsePacket;
 import org.glassfish.grizzly.http.Method;
 import org.glassfish.grizzly.http.Protocol;
-import org.glassfish.grizzly.http.util.Charsets;
+import org.glassfish.grizzly.utils.Charsets;
 import org.glassfish.grizzly.http.util.CookieSerializerUtils;
 import org.glassfish.grizzly.http.util.DataChunk;
 import org.glassfish.grizzly.http.util.Header;

src/main/java/com/ning/http/client/providers/grizzly/GrizzlyResponse.java

@@ -23,7 +23,7 @@
 
 import org.glassfish.grizzly.Buffer;
 import org.glassfish.grizzly.http.CookiesBuilder;
-import org.glassfish.grizzly.http.util.Charsets;
+import org.glassfish.grizzly.utils.Charsets;
 import org.glassfish.grizzly.memory.Buffers;
 import org.glassfish.grizzly.memory.MemoryManager;
 import org.glassfish.grizzly.utils.BufferInputStream;