Update okhttp to a more recent commit.

Updating to upstream commit : 7b106923e078ac2435e8c8ce9d615f9903106ed8
/ 7th Mar 2014 / main branch.

The following changes were made to Android-only code:
1) HttpsHandler has been changed to deal with the fix for:
https://github.com/square/okhttp/issues/184 (commit 5d7fdba).
2) Platform.java changed to accomodate changes in okhttp Platform
method signatures.
3) .mk file updates to reflect src directory changes.

The following changes were made to OkHttp code:
1) Removal of org.codehaus.mojo.animal_sniffer.IgnoreJRERequirement
annotation from okio/src/main/java/okio/DeflaterSink.java

Change-Id: I644a883482ac7ee7d029785f110a2ca00762419b
diff --git a/android/main/java/com/squareup/okhttp/HttpHandler.java b/android/main/java/com/squareup/okhttp/HttpHandler.java
index c656c04..a7179bd 100644
--- a/android/main/java/com/squareup/okhttp/HttpHandler.java
+++ b/android/main/java/com/squareup/okhttp/HttpHandler.java
@@ -19,6 +19,7 @@
 
 import java.io.IOException;
 import java.net.Proxy;
+import java.net.ResponseCache;
 import java.net.URL;
 import java.net.URLConnection;
 import java.net.URLStreamHandler;
@@ -46,6 +47,11 @@
             client.setProxy(proxy);
         }
 
+        // Explicitly set the response cache.
+        ResponseCache responseCache = ResponseCache.getDefault();
+        if (responseCache != null) {
+          client.setResponseCache(responseCache);
+        }
         return client;
     }
 }