Added a EVP_CIPHER_CTX_init() call

* In OpenSSL when you alloc an EVP_CIPHER_CTX you must then init it
  (which just zeroes the allocated memory). If you do not then it is
  possible for things to kerplode when passing the uninitialized context
  to EVP_EncryptInit_ex(). This patch fixes that.
Merge pull request #79 from reaperhulk/init-cipher-ctx

Added a EVP_CIPHER_CTX_init() call