Pkeyauth flag fix to master

<a href='#crh-start'></a><a href='#crh-data-%7B%22processed%22%3A%20%5B%22https%3A//github.com/AzureAD/azure-activedirectory-library-for-objc/pull/234%23issuecomment-66691269%22%5D%2C%20%22comments%22%3A%20%7B%22General%20Comment%22%3A%20%7B%22html_url%22%3A%20%22https%3A//github.com/AzureAD/azure-activedirectory-library-for-objc/pull/234%23issuecomment-66691269%22%2C%20%22comments%22%3A%20%5B%7B%22body%22%3A%20%22Changes%20looks%20good%2C%20but%20one%20test%20is%20failing.%22%2C%20%22created_at%22%3A%20%222014-12-11T21%3A23%3A21Z%22%2C%20%22user%22%3A%20%7B%22avatar_url%22%3A%20%22https%3A//avatars.githubusercontent.com/u/466805%3Fv%3D3%22%2C%20%22html_url%22%3A%20%22https%3A//github.com/omercs%22%7D%7D%5D%2C%20%22title%22%3A%20%22General%20Comment%22%7D%7D%7D'></a>
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- [ ] <a href='#crh-comment-General Comment'></a> <img src='http://www.codereviewhub.com/site/github-remaining.png' height=16 width=60>&nbsp;<b><a href='https://github.com/AzureAD/azure-activedirectory-library-for-objc/pull/234#issuecomment-66691269'>General Comment</a></b>
- <a href='https://github.com/omercs'><img border=0 src='https://avatars.githubusercontent.com/u/466805?v=3' height=16 width=16'></a> Changes looks good, but one test is failing.


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