Remove redundant use of HttpClient

[theScrabi]

With the changes done by removing the ok http singleton I also introduced a redundend use of the HttpClient wrapper.

The HttpClient gets introduced to the HttpMethod through the constructor:

android-library/owncloudComLibrary/src/main/java/com/owncloud/android/lib/common/http/methods/HttpBaseMethod.kt

Lines 15 to 17 in 9d80a95

	abstract class HttpBaseMethod constructor(clientWrapper: HttpClient, url: URL) {
	var okHttpClient: OkHttpClient

However the execute() method of the HttpMethod is later called from the OwnCloudClient which extends the HttpClient wrapper:

android-library/owncloudComLibrary/src/main/java/com/owncloud/android/lib/common/OwnCloudClient.java

Lines 94 to 110 in b96a3e9

	public int executeHttpMethod(HttpBaseMethod method) throws Exception {
	boolean repeatWithFreshCredentials;
	int repeatCounter = 0;
	int status;
	do {
	String requestId = RandomUtils.generateRandomUUID();
	// Header to allow tracing requests in apache and ownCloud logs
	Timber.d("Executing in request with id %s", requestId);
	method.setRequestHeader(HttpConstants.OC_X_REQUEST_ID, requestId);
	method.setRequestHeader(HttpConstants.USER_AGENT_HEADER, SingleSessionManager.getUserAgent());
	method.setRequestHeader(HttpConstants.ACCEPT_ENCODING_HEADER, HttpConstants.ACCEPT_ENCODING_IDENTITY);
	if (mCredentials.getHeaderAuth() != null && method.getRequestHeader(AUTHORIZATION_HEADER) == null) {
	method.setRequestHeader(AUTHORIZATION_HEADER, mCredentials.getHeaderAuth());
	}
	status = method.execute();

Getting "in touch" twice with the client is redundant and should be removed. Here are two possible solutions:

1. Try to Inject the client from the constructor:

The HttpClient modifying methods in the `HttpBaseMethod` do not need to be changed: https://github.com/owncloud/android-library/blob/9d80a95a884715f9d71aa16f86bd36d0d50bce14/owncloudComLibrary/src/main/java/com/owncloud/android/lib/common/http/methods/HttpBaseMethod.kt#L110

But the code calling the method.execute() in the OwnCloudClient has to be moved to the HttpMethod:

android-library/owncloudComLibrary/src/main/java/com/owncloud/android/lib/common/OwnCloudClient.java

Line 95 in 9d80a95

public int executeHttpMethod(HttpBaseMethod method) throws Exception {

2. Try to inject the client from the execute method:

The HttpClient modifying methods in the `HttpBaseMethod` need to be modified: https://github.com/owncloud/android-library/blob/9d80a95a884715f9d71aa16f86bd36d0d50bce14/owncloudComLibrary/src/main/java/com/owncloud/android/lib/common/http/methods/HttpBaseMethod.kt#L110

Instead of modifying the OkHttp client directly we could save the modifications and apply them when calling the execute(client) method.
The only change that need to be applied to OwnCloudClient would be that this is suplied the the execution() method.

---

Issue: #378
Library: #427
App: owncloud/android#3353

[jesmrec]

Done