Simplify some logic in EVP_EncryptInit_ex()

Simplify some logic in EVP_EncryptInit_ex()

Pull up the EVP_R_NO_CIPHER_SET check that was hidden somewhere down in the
middle of the function. Handle the reuse case outside of the big non-NULL
cipher case for now. This looks a bit odd but relies on the invariant that
cipher_data is only set if the cipher is set. It will be reworked in a
subsequent commit.

ok jsing