Clean up dart:io warnings/errors found by analyzer tests.

sdk/lib/io/link.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of dart.io;
 
 /**
  * [Link] objects are references to filesystem links.
  *
  */
@@ skipping 159 matching lines @@
   }
 
   // Put target into the form "\??\C:\my\target\dir".
   String _makeWindowsLinkTarget(String target) {
     if (target.startsWith('\\??\\')) {
       return target;
     }
     if (!(target.length > 3 && target[1] == ':' && target[2] == '\\')) {
       try {
         target = new File(target).fullPathSync();
-      } catch (e) {
+      } on FileException catch (e) {
         throw new LinkException('Could not locate target', target, e.osError);
       }
     }
     if (target.length > 3 && target[1] == ':' && target[2] == '\\') {
       target = '\\??\\$target';
     } else {
       throw new LinkException(
           'Target $target of Link.create on Windows cannot be converted' +
           ' to start with a drive letter.  Unexpected error.');
     }
@@ skipping 117 matching lines @@
       if (path != null) {
         sb.write(", path = $path");
       }
     }
     return sb.toString();
   }
   final String message;
   final String path;
   final OSError osError;
 }