[Singers] fixed openssl_pkcs7_encrypt() not using the encryptCipher
merged branch sstok/patch-2 (PR #345)

This PR was merged into the master branch.

Discussion
----------

[Singers] fixed openssl_pkcs7_encrypt() not using the encryptCipher

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #340
| License       | MIT

Swift_Signers_SMimeSigner did not use $encryptCipher, making it always use the the weakest cipher OPENSSL_CIPHER_RC2_40

Commits
-------

91e36e5 [Singers] fixed openssl_pkcs7_encrypt() not using the encryptCipher