Remove an unneccessary check of cipher

Due to short-circuiting we only need to check "cipher" for NULL once.

PR#699
Reviewed-by: NRichard Levitte <levitte@openssl.org>

crypto/evp/evp_enc.c

@@ -120,7 +120,7 @@ int EVP_CipherInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher,
      * reinitialisation, when it may all be unnecessary.
      */
     if (ctx->engine && ctx->cipher
-        && (!cipher || (cipher && (cipher->nid == ctx->cipher->nid))))
+        && (cipher == NULL || cipher->nid == ctx->cipher->nid))
         goto skip_to_init;
 #endif
     if (cipher) {