Fixed whitespace options in Differential.

Summary:
Whitespace options could not be selected and the 'ignore_all' was not working.

Test Plan:
Made sure that whitespace is ignored correctly and selected option is handled
correctly.

Reviewed By: jungejason
Reviewers: jungejason
CC: epriestley, jungejason, tuomaspelkonen
Differential Revision: 149

src/applications/differential/controller/changesetview/DifferentialChangesetViewController.php

@@ -132,6 +132,7 @@ class DifferentialChangesetViewController extends DifferentialController {
     $parser->setChangeset($changeset);
     $parser->setRightSideCommentMapping($right_source, $right_new);
     $parser->setLeftSideCommentMapping($left_source, $left_new);
+    $parser->setWhitespaceMode($request->getStr('whitespace'));
 
     $phids = array();
     $inlines = $this->loadInlineComments($id, $author_phid);