Upgrade to OkHttp3

Summary:
Update to [OkHttp](https://github.com/square/okhttp) to [OkHttp3](https://publicobject.com/2015/12/12/com-squareup-okhttp3/)

We must also update:
- Fresco to 0.10.0
- okio to 1.8.0

**Motivation**
Reasons for upgrading:
* Issue #4021
* "We discovered that RN Android sometimes fails to connect to the latest stable version of NGINX when HTTP/2 is enabled. We aren't seeing errors with other HTTP clients so we think it's specific to RN and OkHttp. Square has fixed several HTTP/2 bugs over the past eight months." - ide
* OkHttp3 will be maintained & improved, but OkHttp2 will only receive [security fixes](https://publicobject.com/2016/02/11/okhttp-certificate-pinning-vulnerability/)
* Cleaner APIs - "Get and Set prefixes are avoided"
* Deprecated/Removed - HttpURLConnection & Apache HTTP
* React Native apps are currently being forced to bundle two versions of OkHttp (v2 & v3), if another library uses v3
* Improved WebSocket performance - [CHANGELOG.md](https://github.com/square/okhttp/blob/master
Closes https://github.com/facebook/react-native/pull/6113

Reviewed By: andreicoman11, lexs

Differential Revision: D3292375

Pulled By: bestander

fbshipit-source-id: 7c7043eaa2ea63f95854108b401c4066098d67f7

ReactAndroid/src/test/java/com/facebook/react/modules/BUCK

@@ -6,8 +6,14 @@ robolectric3_test(
   name = 'modules',
   srcs = glob(['**/*.java']),
   deps = [
+    react_native_dep('libraries/fbcore/src/test/java/com/facebook/powermock:powermock'),
+    react_native_dep('third-party/java/fest:fest'),
+    react_native_dep('third-party/java/junit:junit'),
+    react_native_dep('third-party/java/mockito:mockito'),
+    react_native_dep('third-party/java/okhttp:okhttp3'),
+    react_native_dep('third-party/java/okio:okio'),
+    react_native_dep('third-party/java/robolectric3/robolectric:robolectric'),
     react_native_target('java/com/facebook/csslayout:csslayout'),
-    react_native_target('java/com/facebook/react:react'),
     react_native_target('java/com/facebook/react/animation:animation'),
     react_native_target('java/com/facebook/react/bridge:bridge'),
     react_native_target('java/com/facebook/react/common:common'),
@@ -19,17 +25,10 @@ robolectric3_test(
     react_native_target('java/com/facebook/react/modules/network:network'),
     react_native_target('java/com/facebook/react/modules/storage:storage'),
     react_native_target('java/com/facebook/react/modules/systeminfo:systeminfo'),
-    react_native_target('java/com/facebook/react/uimanager:uimanager'),
     react_native_target('java/com/facebook/react/touch:touch'),
-
+    react_native_target('java/com/facebook/react/uimanager:uimanager'),
+    react_native_target('java/com/facebook/react:react'),
     react_native_tests_target('java/com/facebook/react/bridge:testhelpers'),
-    react_native_dep('libraries/fbcore/src/test/java/com/facebook/powermock:powermock'),
-    react_native_dep('third-party/java/robolectric3/robolectric:robolectric'),
-    react_native_dep('third-party/java/fest:fest'),
-    react_native_dep('third-party/java/junit:junit'),
-    react_native_dep('third-party/java/okio:okio'),
-    react_native_dep('third-party/java/mockito:mockito'),
-    react_native_dep('third-party/java/okhttp:okhttp'),
   ],
   visibility = [
     'PUBLIC'