Fix PageHeader logo size

src/components/PageHeader/index.less

@@ -31,6 +31,12 @@
     flex: 0 1 auto;
     margin-right: 16px;
     padding-top: 1px;
+    > img {
+      width: 28px;
+      height: 28px;
+      border-radius: @border-radius-base;
+      display: block;
+    }
   }
 
   .title {