Don't show placeholder when we have loaded the avatar image

Fixes #6618
Else it shows up as background to transparent avatars

Signed-off-by: Roeland Jago Douma <roeland@famdouma.nl>

core/js/jquery.avatar.js

@@ -148,6 +148,7 @@
 				$div.show();
 				$div.text('');
 				$div.append(img);
+				$div.clearimageplaceholder();
 			};
 
 			img.width = size;

core/js/placeholder.js

@@ -148,4 +148,13 @@
 			this.html(text[0].toUpperCase());
 		}
 	};
+
+	$.fn.clearimageplaceholder = function() {
+		this.css('background-color', '');
+		this.css('color', '');
+		this.css('font-weight', '');
+		this.css('text-align', '');
+		this.css('line-height', '');
+		this.css('font-size', '');
+	};
 }(jQuery));