remove unneeded AES conditionals now that we no longer support 0.9.8 (#2985)

* remove unneeded AES conditionals now that we no longer support 0.9.8

* This comment was inaccurate. EVP AES CTR is available in 1.0.1+, not 1.0.0.

* update function definition to match 1.0.0 and move to functions
2 files changed