Add |EVP_rc2_cbc| and implement |EVP_CTRL_SET_RC2_KEY_BITS|.

Add it to |EVP_get_cipherbynid|, along with |EVP_rc2_40_cbc| and
|EVP_aes_192_cbc|.

Change-Id: Iee7621a91262359d1650684652995884a6cef37a
Reviewed-on: https://boringssl-review.googlesource.com/5590
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/include/openssl/cipher.h b/include/openssl/cipher.h
index 6aab5b1..eb00082 100644
--- a/include/openssl/cipher.h
+++ b/include/openssl/cipher.h
@@ -102,6 +102,9 @@
  * ciphertext. */
 OPENSSL_EXPORT const EVP_CIPHER *EVP_enc_null(void);
 
+/* EVP_rc2_cbc returns a cipher that implements 128-bit RC2 in CBC mode. */
+OPENSSL_EXPORT const EVP_CIPHER *EVP_rc2_cbc(void);
+
 /* EVP_rc2_40_cbc returns a cipher that implements 40-bit RC2 in CBC mode. This
  * is obviously very, very weak and is included only in order to read PKCS#12
  * files, which often encrypt the certificate chain using this cipher. It is