cleanup build warnings
1. Change `CyaSSL_OCSP_set_options()` to return `SSL_SUCCESS`
   or `SSL_FAILURE` as `int` like rest of API.
2. Fix data narrowing warning in file io.c function
   `process_http_response()`.
3. Fix global variable shadowed warning in file ssl.c function
   `CyaSSL_GetSessionAtIndex()`
4. Fix data narrowing warning in file internal.c functions
   `Encrypt()` and `Decrypt()`. Passed in a word32 size parameter
   that was provided a word16 and used as a word16.
5. Removed unreachable code from file tls.c function
   `CyaSSL_GetHmacType()`.
6. Fix data narrowing warnings in file aes.c functions
   `AesCcmEncrypt()` and `AesCcmDecrypt()`.
Merge branch 'master' of github.com:cyassl/cyassl