Fix erroneous semicolon causing build failure: if statement has empty body [-Werror,-Wempty-body]
https://bugs.webkit.org/show_bug.cgi?id=108241

Patch by Kiran Muppala <cmuppala@apple.com> on 2013-01-29
Reviewed by Anders Carlsson.

* UIProcess/WebProcessProxy.cpp:
(WebKit::WebProcessProxy::addExistingWebPage): Remove erroneous
semicolon following the if condition.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@141180 268f45cc-cd09-0410-ab3c-d52691b4dbfc