fix user avatar fallback logic

src/components/user_avatar/user_avatar.js

@@ -16,7 +16,7 @@ const UserAvatar = {
   },
   computed: {
     imgSrc () {
-      return this.showPlaceholder ? '/images/avi.png' : this.src
+      return this.showPlaceholder ? '/images/avi.png' : this.user.profile_image_url_original
     }
   },
   methods: {

src/components/user_avatar/user_avatar.vue

@@ -3,7 +3,7 @@
     class="avatar"
     :alt="user.screen_name"
     :title="user.screen_name"
-    :src="user.profile_image_url_original"
+    :src="imgSrc"
     :class="{ 'avatar-compact': compact, 'better-shadow': betterShadow }"
     :image-load-error="imageLoadError"
   />