Add missing selector to mocked object to fix unit tests with Xcode 5

Unit tests on iOS were broken with Xcode 5 due to the absence of the selector
copyWithZone: from the mocked object. Add the missing selector.

This patches in OCMock e8a9cc97936bfa8be97706c5092110603745e708, "Small changes
for compatibility with Xcode 5 Preview."

BUG=256608,256607
TEST=None

Review URL: https://codereview.chromium.org/186193003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@255011 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 255011