Fixed some typos, courtesy of codespell

src/libstrongswan/plugins/openssl/openssl_pkcs7.c

@@ -357,7 +357,7 @@ METHOD(enumerator_t, signature_enumerate, bool,
 		if (openssl_asn1_known_oid(sig->algorithm) == OID_RSA_ENCRYPTION)
 		{
 			/* derive the signature scheme from the digest algorithm
-			 * for the classic PKCS#7 RSA mechansim */
+			 * for the classic PKCS#7 RSA mechanism */
 			sig_alg.scheme = signature_scheme_from_oid(hash_oid);
 		}
 		else

src/libstrongswan/plugins/pkcs7/pkcs7_signed_data.c

@@ -475,7 +475,7 @@ static bool parse(private_pkcs7_signed_data_t *this, chunk_t content)
 						info->digest_alg != OID_UNKNOWN)
 					{
 						/* derive the signature scheme from the digest algorithm
-						 * for the classic PKCS#7 RSA mechansim */
+						 * for the classic PKCS#7 RSA mechanism */
 						info->sig_alg.scheme = signature_scheme_from_oid(
 															info->digest_alg);
 					}