MXImageView: use the new interface [setImageURI:...] instead of the deprecated one [setImageURL:...] .

Note - DirectoryServerTableViewCell:
Presently the thirdPartyProtocolInstance.icon is not a Matrix Content URI. We could not use here MXKImageView setImageURI method
 without breaking the instance icon rendering. We use the deprecated interface until this point is fixed on the server side.

Riot/Modules/Room/Views/BubbleCells/RoomMembershipCollapsedBubbleCell.m

@@ -1,5 +1,6 @@
 /*
  Copyright 2017 Vector Creations Ltd
+ Copyright 2018 New Vector Ltd
  
  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
@@ -65,14 +66,8 @@
     {
         MXKImageView *avatarView = [[MXKImageView alloc] initWithFrame:CGRectMake(12 * self.avatarsView.subviews.count, 0, 16, 16)];
 
-        // Handle user's picture
-        NSString *avatarThumbURL = nil;
-        if (nextBubbleData.senderAvatarUrl)
-        {
-            // Suppose this url is a matrix content uri, we use SDK to get the well adapted thumbnail from server
-            avatarThumbURL = [nextBubbleData.mxSession.matrixRestClient urlOfContentThumbnail:nextBubbleData.senderAvatarUrl toFitViewSize:avatarView.frame.size withMethod:MXThumbnailingMethodCrop];
-        }
-
+        // Handle user's picture by considering it is stored unencrypted on Matrix media repository
+        
         // Use the Riot style placeholder
         if (!nextBubbleData.senderAvatarPlaceholder)
         {
@@ -80,7 +75,13 @@
         }
         
         avatarView.enableInMemoryCache = YES;
-        [avatarView setImageURL:avatarThumbURL withType:nil andImageOrientation:UIImageOrientationUp previewImage: nextBubbleData.senderAvatarPlaceholder];
+        [avatarView setImageURI:nextBubbleData.senderAvatarUrl
+                       withType:nil
+            andImageOrientation:UIImageOrientationUp
+                  toFitViewSize:avatarView.frame.size
+                     withMethod:MXThumbnailingMethodCrop
+                   previewImage:nextBubbleData.senderAvatarPlaceholder
+                   mediaManager:nextBubbleData.mxSession.mediaManager];
 
         // Clear the default background color of a MXKImageView instance
         avatarView.defaultBackgroundColor = [UIColor clearColor];