Removing extraneous IE search clear button

Taken from http://stackoverflow.com/questions/14007655/remove-ie10s-clear-field-x-button-on-certain-inputs.
Not yet tested, but will be soon.

lms/static/sass/_developer.scss

@@ -312,6 +312,13 @@
       font: inherit;
     }
   }
+  //end instructor tools scratch space
+
+  //efischer TNL-3226
+  .search-field::-ms-clear {
+    width: 0px;
+    height: 0px;
+  }
 }
 
 //efischer - TNL-3189