icons: Clean up file_selected.svg

Remove metadata and clean up the SVG tags to make it simpler.

src/default-theme/icons/md/file_selected.svg

@@ -1,12 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
-<!-- Generator: Adobe Illustrator 19.2.1, SVG Export Plug-In . SVG Version: 6.00 Build 0)  -->
-<svg version="1.1" id="Layer_1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" x="0px" y="0px"
-	 viewBox="0 0 18 18" style="enable-background:new 0 0 18 18;" xml:space="preserve">
-<style type="text/css">
-	.st0{fill:#FFFFFF;}
-	.st1{fill:none;}
-</style>
-<path class="st0" d="M4.5,1.5C3.7,1.5,3,2.2,3,3l0,12c0,0.8,0.7,1.5,1.5,1.5h9c0.8,0,1.5-0.7,1.5-1.5V6l-4.5-4.5H4.5z M9.8,6.8V2.6
-	l4.1,4.1H9.8z"/>
-<path class="st1" d="M0,0h18v18H0V0z"/>
+<svg version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" viewBox="0 0 18 18">
+    <path fill="#FFFFFF" d="M4.5,1.5C3.7,1.5,3,2.2,3,3l0,12c0,0.8,0.7,1.5,1.5,1.5h9c0.8,0,1.5-0.7,1.5-1.5V6l-4.5-4.5H4.5z M9.8,6.8V2.6
+    l4.1,4.1H9.8z"/>
+    <path fill="none" d="M0,0h18v18H0V0z"/>
 </svg>