Fix two failing tests under io.js

Two tests were failing under io.js because the error message formatting
has changed. Since io.js is the future Node.js, we'd have to fix this
sooner or later. :-)

See nodejs/node@bc2c85c and nodejs/node#212 for details.

Author: Tom X. Tobin

test/fromfile.js

@@ -49,15 +49,15 @@ describe('from file', function () {
       function () {
         args = parser.parseArgs(['@invalid']);
       },
-      /ENOENT, no such file or directory/
+      /ENOENT[:,] no such file or directory/
     );
   });
   it('test reading arguments from an missing file', function () {
     assert.throws(
       function () {
         args = parser.parseArgs(['@missing']);
       },
-      /ENOENT, no such file or directory/
+      /ENOENT[:,] no such file or directory/
     );
   });
   it('test custom convertArgLineToArgs function', function () {