Remove load_hkdf_vectors which snuck in with a rebase.
Remove load_hkdf_vectors which snuck in with a rebase.

bwhmather/cryptography,sholsapp/cryptography,dstufft/cryptography,bwhmather/cryptography,kimvais/cryptography,Lukasa/cryptography,Lukasa/cryptography,skeuomorf/cryptography,Hasimir/cryptography,bwhmather/cryptography,Ayrx/cryptography,kimvais/cryptography,sholsapp/cryptography,sholsapp/cryptography,dstufft/cryptography,Hasimir/cryptography,sholsapp/cryptography,Lukasa/cryptography,kimvais/cryptography,skeuomorf/cryptography,Ayrx/cryptography,skeuomorf/cryptography,Hasimir/cryptography,kimvais/cryptography,dstufft/cryptography,skeuomorf/cryptography,bwhmather/cryptography,Hasimir/cryptography,Ayrx/cryptography,dstufft/cryptography,Ayrx/cryptography,dstufft/cryptography