fix theme hovercard on all pages (bug 905425)

media/css/impala/hovercards.less

@@ -115,7 +115,7 @@
             overflow: hidden;
             position: relative;
             img {
-                width: 200px;
+                width: auto;
                 height: 67px;
                 position: absolute;
                 right: 0;
@@ -406,7 +406,3 @@
 .hovercard .install-shell .d2c-reasons-help {
     display: none;
 }
-
-.hovercard .persona-preview img {
-    width: auto;
-}